Erythromycin is an older medication, and clinical studies did not break down side effects into exact percentages. Thus, while possible side effects are known, it is hard to say exactly how common they are. In addition, the adverse reactions a person may experience can vary, based on the form of erythromycin that is being used.
However, some side effects of erythromycin are more common than others -- in particular, digestive-related side effects, such as
diarrhea, nausea, and vomiting. In fact, these side effects are often so expected that erythromycin is sometimes used in an
off-label fashion to treat a condition called
diabetic gastroparesis because it makes food move faster through the digestive tract.
(Click Erythromycin Side Effects to learn more about the possible problems a person may experience with this drug, including serious reactions that may require prompt medical care.)