Penicillin V potassium should not be used for extended periods. If diarrhea is severe or lasts more than 2 or 3 days, contact your doctor, as this may be a sign of an infection of the bowels. Sometimes after starting treatment with antibiotics, patients can develop watery and bloody stools (with or without stomach cramps and fever) even as late as 2 or more months after having taken their last dose of the antibacterial. Diarrhea is a common problem caused by antibiotics, and it usually ends when the antibacterial is discontinued. Despite a few variations from telling to telling, the story remains the samethe Queen was jealous of the girl’s beauty, and this jealousy culminated in the Queen’s attempt on the sweet, naive girl’s life. swelling of the face, eyes, lips, tongue, arms, or legs From Book 1: The tale of the young princess and her evil stepmother, the Wicked Queen, is widely known.Tell your healthcare provider right away if you start to develop signs or symptoms of a hypersensitivity reaction, which include the following: These reactions are more likely to occur in those with a history of penicillin hypersensitivity and/or a history of sensitivity to multiple allergens. This type of reaction may be serious and possibly fatal. hypersensitivity (severe allergic reaction).Serious side effects have been reported with penicillin V potassium including: