Sobrerol is an agent with a terpenic structure used to modify mucus characteristics in patients with hypersecretory bronchopulmonary diseases and this review is aimed at listing and discussing all the scientific evidence on this drug. All the toxicological findings testify its excellent tolerability and very low toxicity. In the pharmacological section of the review the effects of sobrerol on mucus production and its characteristics are discussed together with its effect on experimental models. A number of open clinical trials suggesting a therapeutic potential activity of the drug is examined together with a series of randomized double-blind clinical trials confirming its efficacy in relieving obstructive symptoms in chronic bronchitic patients.