# Common Side Effects

Common Side Effects is an American adult animated television series created by Joseph Bennett and Steve Hely for Cartoon Network's Adult Swim block.
The pilot episode premiered privately at the Annecy International Animation Film Festival in June 2024, and publicly a month later at Adult Swim's San Diego Comic-Con panel in July 2024. The series premiered on Adult Swim on February 2, 2025, to critical acclaim. The series has an encore broadcast on the network's Toonami programming block that began on March 2, 2025.

## Premise

Two high school friends, Marshall and Frances, reconnect and discover the Blue Angel Mushroom, a mushroom that acts as a drug that can allegedly cure all illnesses. In the process, they also uncover a conspiracy involving Reutical Pharmaceuticals, Inc., one of the largest pharmaceutical companies and the government to suppress all knowledge of said drug.

## Characters
### Main

* Marshall Cuso (voiced by Dave King) is the knowledgeable, cautious protagonist of the series and was friends with Frances in high school. He is an accomplished expert in fungi who has done charity work in foreign countries and is sly in run-ins with the DEA.
* Frances Applewhite (voiced by Emily Pendergast) is Rick's executive assistant and Marshall's high school lab mate and friend. Though initially hesitant about the effects of the Blue Angel, she eventually sees the monetary value in the mushrooms and is motivated to try and get them to Rick to take care of her mother, who was recently diagnosed with dementia.
* Agents Copano (voiced by Joseph Lee Anderson) and Harrington (voiced by Martha Kelly) are nonchalant best friends who work for the Drug Enforcement Administration. Kelly describes Harrington as "goofy but is very pragmatic about [her] job.", while Anderson describes Copano as someone who is "big on conspiracy theories" and who likes to "connect dots when they probably should not be connected."
* Rick Kruger (voiced by Mike Judge) is the incompetent chief executive officer of Reutical, who constantly bothers Frances to do mundane tasks for him, such as booking reservations and changing the TV channel. He also enjoys farming simulator video games, often playing in improper settings such as work and formal events.

### Recurring

* Nick (voiced by Ben Feldman) Frances' lackadaisical, often oblivious boyfriend who loves VR gaming.
** Feldman also voices Bud Budrigger
* Jonas Backstein (voiced by Danny Huston) is a Swiss powerful board member of Reutical, with heavy insider ties to the federal government, and focused on destroying Marshall and the mushrooms.
* Cecily (voiced by Sydney Poitier) is a politician who is backed financially by Jonas in hopes she’ll do his bidding in the interest of Reutical.
* Hildy (voiced by Sue Rose) is Marshall's idiosyncratic, mycologist mentor who is skeptical of Frances' motive for working with Marshall once she is healed by the mushroom.
* Sonia Applewhite (voiced by Lin Shaye) is Frances' mother who has been diagnosed with dementia, and is Frances' main motivation for acquiring the Blue Angel mushroom.
* Amelia (voiced by Shannon Woodward) is the laid-back mycologist hired by the DEA to gather information on the Blue Angel, also acting as a single mother and caretaker to her ill son, Wyatt. Woodward also provides additional voices.
* Kiki (voiced by Christine Ko) is a researcher at Reutical. Young and knowledgeable on medicine and the pharmaceutical system, she acts as the devil's advocate for the company, disputing the arguments brought up by people such as Marshall.
* Kenji is Copano and Harrington's boss at the DEA.

### Additional / Guest voices

* Shalita Grant as Female DEA Agent / Susan
* Bob Stephenson as Connor / Samurai
* Alan Resnick as Zane
* Timothy Simons as DEA Dispatcher / Lawyer
* Andy Daly as Mysterious Passenger / Christopher
* Nicolas Cantu as Tommy

## Episodes

| No. | Title | Directed by | Written by | Original release date | US viewers (millions) |
| 1 | "Pilot" | Camille Bozec | Joe Bennett & Steve Hely | February 2, 2025 (2025-2-2) | 0.18 |
| After being escorted out of a Reutical Pharmaceutical event, shareholder Marshall Cuso reunites with high school friend Frances Applewhite and tells her about a new drug he discovered that acts as a panacea. While Marshall shows the drug's effect, a DEA agent takes photos of the two and brings them back to the DEA, who assign agents Copano and Harrington to surveil Marshall. The two talk at a coffee shop, where Marshall explains how he found this drug that comes from a mushroom that only grows in the Peruvian Highlands. He also states that Reutical has a plant upstream from the valley where the mushroom grows and is risking polluting the area. While Frances takes a call, Marshall becomes paranoid that he is being watched and followed and quickly leaves the coffee shop. Frances talks to her boss, Rick Kruger, CEO of Reutical, about a new drug she's been "exploring." Marshall goes back to his house, where his security system is going off and the DEA conducts a raid on his home. Marshall escapes and calls Frances. ||||||
| 2 | "Lakeshore Limited" | Sean Buckelew | Steve Hely | February 2, 2025 (2025-2-2) | 0.18 |
| Connor, a Reutical employee working at the Peru facility, is meeting with Cecily, a politician who is financed by Reutical. Connor recounts discovering Marshall's use of the mushroom (revealed to be a blue angel mushroom) to a local child who had been injured and instantly cured. Cecily, unsure of the story's validity and what she should or can do about it, is confronted by Jonas Backstein, a Reutical board member, and Connor demonstrates the mushroom's ability. Cecily escalates the situation with the government and Jonas hires bounty hunters to kill Marshall. Meanwhile, Marshall, still on the run, tries meeting with Frances and briefly sees his half-brother, Zane, to help Marshall's tortoise. Copano and Harrington begin to question why they are sent to stake out Marshall's home. Frances continues researching the blue angel to bring to Reutical, going to Marshall's house to learn more. On the run, Marshall arranges to have his notes destroyed and his pets moved. However, the men sent to handle this accidentally burn down his house with Frances narrowly escaping. The bounty hunters hit Marshall's car, but he escapes after taking some blue angel mushrooms and takes the train out of town. Copano and Harrington arrive back at Marshall's house after picking up a mycologist to find it burned. Jonas gets confirmation that Marshall has escaped, and then has Connor shot in the head to ensure total destruction of the blue angel mushroom. ||||||
| 3 | "Hildy" | Vincent Tsui | Emma Barrie | February 9, 2025 (2025-2-9) | 0.14 |
| On the train, some undercover agents attempt to apprehend Marshall, but he gets away. Meanwhile, Frances, recovering from her trauma, goes to her mother's space, and talks to her about the recent events, apologizing for not visiting earlier. Then, Frances finds an envelope from Marshall containing a Blue Angel mushroom, and an accompanying note. She then mixes it with Sonia's food, under the guise that it will heal her. It fails, and Frances, disappointed. With no mode of transport, Marshall rents a vehicle to drive to the home of his mentor, Hildy. On the way, he notices someone get into a fatal car accident, and feeds him a mushroom. He arrives at Hildy's house to inform her about his possession of the Blue Angel. Skeptical, she questions him on how he found it and reveals that its properties come from natural adaptation to Reutical's environmental pollution. When Hildy realizes he is telling the truth, she asks him to show it. Attempting to prove its effectiveness, she pulls a revolver out of a drawer and commits suicide. Panicked, Marshall feeds her a mushroom, where she has a hallucination of her head aging rapidly and exploding into bacteria over and over, which turns into a blue ball which is taken from her. Afterwards, Marshall tries to plan with her to grow more by a medical waste site. She rejects the plan and Marshall leaves her, to which Hildy decides to hunt him down. Later, it is revealed that the mushroom given to the car crash victim works and he survives. Additionally, Sonia sees the same figure that others given the Blue Angel see when it kicks in and greets it. ||||||
| 4 | "Dumpsite" | Camille Bozec | Jean Kyoung Frazier | February 16, 2025 (2025-2-16) | N/A |
| Frances and Nick have sex on the work trip, where Frances falsely says she wants to marry him, causing them to have an argument. She then gets a call from her mom's receptionist, who tells her that her mom has seemingly lost her dementia. She then leaves Rick and Nick to see her mom, where she finds that the mushroom really did heal her mom, and they have their first conversation in years. She then decides to locate Marshall and help him. Meanwhile, Marshall decides to purchase a plot of land near a chemical waste site with the intention of growing more of his revolutionary medicinal mushrooms there, believing the contaminated soil might enhance their properties. He finds the neighbors near the dumpsite think of him as suspicious, but he still uses one of his three remaining mushrooms to attempt to recreate the environment, which fails. Eventually, Frances and Marshall reunite, and Frances thanks him. She decides to try and help Marshall, but they are cut short when some agents try to kill Marshall. He is pursued by one of them on a bike, but the agent is violently blown up by a hidden mine. ||||||
| 5 | "Star-Tel-Lite" | Sean Buckelew | Dave King | February 23, 2025 (2025-2-23) | 0.19 |
| Marshall and Frances' neighbors take in the both of them after Marshall heals their dying son, Tommy by using their second to last mushroom. Frances records this and sends this to Rick, and Rick shows it to Jonas, who claims that the video is fake and Rick should get another job. Meanwhile, Copano and Harrington find where Marshall is located and secretly implement spy cameras by posing as a TV dish company known as "Star-Tel-Lite." When Marshall and Frances go to the store, Frances is confronted by Hildy and her gang, but she quickly leaves. Later, Marshall and Frances go to the forest with Socrates, where Socrates leads the path on where to grow their final mushroom. The next day, Marshall and Frances find out that the mushrooms have regrown, and they take one even though they are healthy to see the side effects. Marshall has a strange hallucination where he sees people getting turned into bacteria by the figures before waking up to police at the door. They tell him that he is under arrest for arson he didn't commit, and before he is sent into jail, Frances kisses Marshall and he is taken away. ||||||
| 6 | "In the System" | Vincent Tsui | Jon Foor | March 2, 2025 (2025-3-2) | TBD |
| Marshall finds himself incarcerated in jail and denied bail, with his lawyer suggesting that someone powerful may be behind it. A hitman robs a convenience store and calls 911 on himself to get sent to jail with Marshall. Copano and Harrington find Socrates, and give him to Frances. Frances takes Socrates and the harvested mushrooms back home, and talks to her mother, who encourages her to take the mushrooms to Reutical. Frances visits Marshall in jail, who tells her to meet him at Joshua Tree National Park if he can escape. After talking to Kiki, who tells her about how Reutical saved lives with a heart disease medication, Frances takes the mushrooms to Kruger, demanding a promotion to head of marketing, money, and other benefits in exchange, which Kruger grants. Copano and Harrington are separated and assigned new partners as punishment for not recovering the mushrooms. Hildy visits Marshall in jail and suggests that Frances has betrayed him. After thinking about Frances's past statements, Marshall calls Reutical, and asks to be forwarded to Frances. Frances, in her new office, picks up and hears noises from the jail, correctly guessing that it is Marshall who has called her. After Marshall silently hangs up, the hitman corners Marshall, pinning him down and preparing to inject him with poison. ||||||
| 7 | "Blowfish" | Camille Bozec | Karey Dornetto | March 9, 2025 (2025-3-9) | TBD |
| A group of other inmates kills the hitman before he can inject Marshall, and demand Marshall use his herbalist knowledge to work for them as a doctor in exchange for saving his life. At her nursing home, Sonia climbs a tree, but dies from a fall after a branch breaks beneath her. Frances is devastated, but is reassured by Kiki and Kruger, and Reutical starts a fund to research the mushroom in her memory. Marshall discovers that Amelia is volunteering at his prison, which she started doing after using the mushroom she found during the DEA investigation to cure her sick son and learning Marshall was there. She offers to help him escape, and Marshall asks her to procure tetrodotoxin for him. She synthesizes it and gives it to him, but unknowingly doubles the dosage. Harrington visits Copano, who suggests that there is a conspiracy involved in the case. In his cell, Marshall drinks the toxin and dies. ||||||
| 8 | "Amelia & Wyatt" | Sean Buckelew | Dan Schofield | March 16, 2025 (2025-3-16) | TBD |
| Marshall wakes up in the morgue, and Amelia unzips his cadaver pouch, saving him from suffocation. Amelia sneaks Marshall out, and along with Amelia's son Wyatt they head to Frances's apartment to retrieve Socrates. At a racecourse, Copano and Harrington surveil a meeting taking place between Jonas and Cecelia, Harrington now convinced to help Copano keep pursuing the case. Frances breaks up with Nick. Jonas forces Rick to shut down Reutical's project commercializing the mushroom, predicting economic collapse, cartel control, and brutal war if the mushroom is made widely available. Marshall confronts Frances over taking the mushroom to Reutical, reclaiming Socrates and his remaining supply. Frances finds a drawing Wyatt left on her apartment wall showing how the mushroom grows in Socrates's feces. Copano and Harrington discover that Amelia checked out Marshall's body from the morgue. Marshall once again visits Zane for help with Socrates, and Wyatt and Marshall independently observe machine elf-like Lilliputian hallucinations that seem to have persisted from the mushroom trip. Jonas learns he has a serious medical issue. Frances is let go from Reutical; Rick, having saved a mushroom after leaving Reutical, offers that they work together. Marshall, Amellia, and Wyatt arrive back at Marshall's trailer near the chemical waste site, to find that Hildy's gang and the neighbors have teamed up, researching how to grow the mushroom. ||||||
| 9 | "Cliff's Edge" | TBA | TBA | March 23, 2025 (2025-3-23) | TBD |
| 10 | "Raid" | TBA | TBA | March 30, 2025 (2025-3-30) | TBD |

## Production
### Development

Common Side Effects co-creators Joseph Bennett and Steve Hely were brought together and began development of the series in 2019 under production studio Bandera Entertainment founded by Mike Judge and Greg Daniels. Bennett and Hely sought to combine the crime thriller genre with comedy, inspired by the films of the Coen brothers, such as Burn After Reading. Inspiration for the story came from the co-creators' interest in medicine and the work of mycologist Paul Stamets, ethnobotanists Richard Evan Schultes, Terence McKenna and Wade Davis, and the chemist Albert Hofmann. The character Marshall was in part inspired by Stamets and "The Orchid Thief" John Laroche as he was portrayed in the film Adaptation. Another inspiration was the story of R. Gordon Wasson publishing an article about Psilocybin mushroooms and María Sabina in Life magazine and the dramatic consequences for the life of Maria Sabina once the article was published.

### Animation

Animation for the series was produced by Green Street Pictures employing an international team of artists, including some working remotely from France, Portugal, Spain, and Mexico. Many of these artists worked on Scavengers Reign, a 2023 series also produced by Green Street and co-created by Bennett. Animation was produced in conjunction with Le Cube, a partner studio in Argentina.

## Release

The series was first announced in June 2023, at the Annecy International Animation Film Festival. The pilot episode premiered privately at the festival event the following year.

## Reception

The review aggregator website Rotten Tomatoes reported a 100% approval rating with an average rating of 8.6/10, based on 20 critic reviews. The website's critics consensus reads, "An addictive mix of expressive animation, heady concepts, and an offbeat sense of humor, Common Side Effects is a must-have prescription." Metacritic, which uses a weighted average, assigned a score of 80 out of 100 based on 6 critics, indicating "Generally Favorable" reviews.