While Rheunac is a very safe drug, it can sometimes cause side effects.
The main reported side effects are mild and should clear up quickly. As with all medications, if any unusual effects are noticed that persist or worsen, report them to your healthcare provider or pharmacist immediately.
The main side effects in breathing that have been noted include additional mucus, sore throat, tight chest or a runny nose.
Other general conditions can be stomatitis (painful swelling or sores on the inside of the mouth), drowsiness, fever, gastrointestinal discomforts such as nausea and vomiting, or clammy skin.