Magic mushrooms are illegal because they contain the illegal substances psilocybin and psilocin. These substances are classified as Schedule I drugs under the United Nations 1971 Convention on Psychotropic Substances. These drugs are considered to have a high potential for abuse and have no approved medical uses. However, some cultures in different countries revere magic mushrooms for their therapeutic abilities. Regardless of whether you believe magic mushrooms may be medicinal, you should not ingest them while pregnant.