The salts pseudoephedrine hydrochloride and pseudoephedrine sulfate are found in many over-the-counter preparations, either as a single ingredient or (more commonly) in combination with antihistamines, guaifenesin, dextromethorphan, paracetamol (acetaminophen), or an NSAID (such as aspirin or ibuprofen).

Pseudoephedrine is a stimulant, but it is well known for shrinking swollen nasal mucous membranes; so, it is often used as a decongestant. It reduces tissue hyperemia, edema, and nasal congestion commonly associated with colds or allergies. Other beneficial effects may include increasing the drainage of sinus secretions, and opening of obstructed Eustachian tubes. The same vasoconstriction action can also result in hypertension, which is a noted side effect of pseudoephedrine.

Pseudoephedrine can be used either as oral or as topical decongestant. The advantage of oral pseudoephedrine over topical nasal preparations, such as oxymetazoline, is that it does not cause rebound congestion (rhinitis medicamentosa). However, due to its stimulating qualities, it is more likely to cause adverse effects, including hypertension, sweating, insomnia, and anxiety.

Pseudoephedrine may be useful as antitussive drug (suppressing of cough).^[8]