Tasted very bad, appeared oily; Baby not able to swallow full dose due to spitting out; Not able to swallow full dose; This non-serious case was reported by a nurse via sales rep and described the occurrence of regurgitation of medication in a 8-week-old female patient who received Rota (Rotarix lyophilized formulation) (batch number YL9YN, expiry date 20-APR-2025) for prophylaxis. This case was associated with a product complaint.   On 18-APR-2023, the patient received the 1st dose of Rotarix lyophilized formulation. On 18-APR-2023, less than a day after receiving Rotarix lyophilized formulation, the patient experienced regurgitation of medication (Verbatim: Baby not able to swallow full dose due to spitting out) and accidental underdose (Verbatim: Not able to swallow full dose). On an unknown date, the patient experienced pharmaceutical product complaint (Verbatim: Tasted very bad, appeared oily). The outcome of the regurgitation of medication was not reported and the outcome of the accidental underdose and pharmaceutical product complaint were unknown.   It was unknown if the reporter considered the regurgitation of medication to be related to Rotarix lyophilized formulation and Rotarix Oral Applicator Device.     It was unknown if the company considered the regurgitation of medication to be related to Rotarix lyophilized formulation and Rotarix Oral Applicator Device.   This report is made by GSK without prejudice and does not imply any admission or liability for the incident or its consequences.   Additional Information: GSK Receipt Date: 21-APR-2023/ 25-APR-2023 The patient was not able to swallow full dose of Rotarix liquid due to spitting out. It was observed that the vaccine tasted very bad and appeared oily as it dribbled out of the corners of the mouth. The patient did not receive a second dose.  The patient made face as if it tasted too bad to swallow. The patient previously had used Rotarix vial presentation and had no problems. The reporter attempted to contact health care professional but did not received answer. The reporter stated that when nurse will call back need to obtain additional information like business name, confirm lot numbers and expiration dates for doses because 12 patients were affected but there are 10 doses in a package, confirm initials, gender, and date of birth for patients.  The reporter wanted to know if suspect products can be returned, if there is any issue in appearance before administration. If yes then asked PQC questions description of approximate size, shape and color, what was different from other vials/syringes if it was cloudier deposit more difficult to put in suspension, color was different or any visible damage present on the vial/syringe, was there any temperature excursions during storage and was the product at room temperature when particle observed. The reporter agreed to follow up from GlaxoSmithKline.  The patient was not able to swallow full dose of Rotarix liquid due to spitting out and observed that the vaccine tasted very bad and appeared oily as it dribbled out of the corners of the mouth, which led to accidental underdose and pharmaceutical product complaint. This was 1 of 12 linked cases, reported by the same reporter.; Sender's Comments:  US-GSK-US2023AMR059808:Same reporter US-GSK-US2023AMR059807:Same reporter US-GSK-US2023AMR059645:Same reporter US-GSK-US2023AMR059644:Same reporter US-GSK-US2023AMR058971:Same reporter US-GSK-US2023AMR060400:Same reporter US-GSK-US2023AMR060460:Same reporter US-GSK-US2023AMR060463:Same reporter US-GSK-US2023AMR060476:Same reporter US-GSK-US2023AMR060400:Same reporter US-GSK-US2023AMR060497:Same reporter US-GSK-US2023AMR060460:Same reporter US-GSK-US2023AMR060463:Same reporter US-GSK-US2023AMR059808:Same reporter US-GSK-US2023060947:Same reporter. FU1 - deleted US-GSK-US2023AMR058971:Same reporter