ATC Code R05CA03
Formula C10H14O4
Molar Mass (g·mol−1) 198,22
Physical State solid
Melting Point (°C) 78–81
Boiling Point (°C) 215
CAS Number 93-14-1
PUB Number 3516
Drugbank ID DB00874
Solubility soluble in water


Guaifenesin is a drug from the group of expectorants (mucolytics). It is used for respiratory infections such as colds and bronchitis and makes it easier to cough up the tough mucus in the lungs. In addition, it helps relieve chest tightness and the urge to cough.

It is available as a juice and in the form of capsules.



Guaifenesin acts by increasing the secretion of mucus while decreasing its viscosity. This promotes the efficiency of ciliary activity in the lungs and makes it easier to clear the airways of irritating substances. The result is easier expectoration of mucus and thus an overall reduction in coughing. The exact mechanism of action is not yet fully understood.


Guaifenesin is absorbed through the mucous membranes of the gastrointestinal tract. The plasma half-life is approximately one hour. The drug is metabolized by the liver and subsequently excreted mainly by the kidneys.

Drug Interactions

Guaifenesin should not be taken together with sedatives or muscle relaxants as their effects are enhanced. In addition, antitussives should not be taken as this may result in a build-up of secretions in the lungs.


Signs of overdose include nausea and vomiting.

Studies have shown that guaifenesin can have a negative effect on the foetus. Therefore, it should not be taken during pregnancy. Guaifenesin can also pass into breast milk in small amounts. It should therefore only be given to nursing mothers if the benefit clearly outweighs the possible risk.

Side effects

Side effects such as hypersensitivity reactions, dizziness, heat sensation, nausea and vomiting are possible.

Toxicological data

LD50: 1510 mg/kg (rat, oral)

Markus Falkenstätter

Markus Falkenstätter

Markus Falkenstätter ist Autor zu pharmazeutischen Themen in der Medizin-Redaktion von Medikamio. Er befindet sich im letzten Semester seines Pharmaziestudiums an der Universität Wien und liebt das wissenschaftliche Arbeiten im Bereich der Naturwissenschaften.

Mag. pharm Stefanie Lehenauer

Mag. pharm Stefanie Lehenauer

Stefanie Lehenauer ist seit 2020 freie Autorin bei Medikamio und studierte Pharmazie an der Universität Wien. Sie arbeitet als Apothekerin in Wien und ihre Leidenschaft sind pflanzliche Arzneimittel und deren Wirkung.

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