Terpin hydrate is an expectorant commonly used to loosen mucus in patients presenting with acute or chronic bronchitis, and related conditions. Terpin is derived from oil of turpentine, oregano, thyme and eucalyptus. In 1855 Lepin who first investigated terpin reported that it acted upon the mucous membranes and also the nervous system in a manner similar to the oil of turpentine. Terpin hydrate was available in the USA in 1907 in the preparations such as Elixir of Terpin Hydrate alone or in combination with codein or heroin as an antitussives. It was banned by the U.S. Food and Drug Administration (FDA) in the 1990s due to lack of proof of efficacy but is a medicine available in a number of countries worldwide commonly used in combination with codein. At present it is FDA approved for as an OTC use in combination formulations (with acetaminophen and other drugs) used as internal analgesics. Terpin was recently introduced as a natural topical insect repellent.

Noscapine (also known as Narcotine, Nectodon, Nospen, Anarcotine and (archaic) Opiane) is a benzylisoquinoline alkaloid from plants of the poppy family, without painkilling properties. This agent is primarily used for its antitussive (cough-suppressing) effects. Noscapine is often used as an antitussive medication. A 2012 Dutch guideline, however, does not recommend its use for coughing. Noscapine can increase the effects of centrally sedating substances such as alcohol and hypnotics. Noscapine should not be taken in conjunction with warfarin as the anticoagulant effects of warfarin may be increased. Noscapine, and its synthetic derivatives called noscapinoids, are known to interact with microtubules and inhibit cancer cell proliferation. Mechanisms for its antitussive action are unknown, although animal studies have suggested central nervous system as a site of action. Furthermore, noscapine causes apoptosis in many cell types and has potent antitumor activity against solid murine lymphoid tumors (even when the drug was administered orally) and against human breast and bladder tumors implanted in nude mice. Because noscapine is water-soluble and absorbed after oral administration, its chemotherapeutic potential in human cancer merits thorough evaluation. Antifibrotic effect of noscapine based on novel mechanism, which it shows through EP2 prostaglandin E2 receptor-mediated activation of protein kinase A.

Guaiacol is a naturally occurring organic compound first isolated by Otto Unverdorben in 1826. Although it is biosynthesized by a variety of organisms, this yellowish aromatic oil is usually derived from guaiacum or wood creosote. Guaiacol is used as a reducing co-substrate for COX reactions. It is mainly used as expectorant, antiseptic. It is used as cough suppressant, it is an ingredient of Pulmo Bailly (UK). Pulmo Bailly Cough Expectorant is indicated for relief for cough symptoms that are associated with a flu, cold, or other infection. It contains active ingredients, Codeine and Guajacol, which reduce discomfort and the urge to cough. Each 5 ml tablespoon of Pulmo Bailly contains 75 mg guaiacol and 7 mg codeine.

Cloperastine (INN) or cloperastin is an antitussive and antihistamine that is marketed as a cough suppressant in Japan, Hong Kong, and in some European countries. It was first introduced in 1972 in Japan, and then in Italy in 1981. The precise mechanism of action of cloperastine is not fully clear, but several different biological activities have been identified for the drug, of which include: ligand of the gamma1 receptor (Ki = 20 nM) (likely an agonist), GIRK channel blocker (described as "potent"), antihistamine (Ki = 3.8 nM for the H1 receptor), and anticholinergic. Cloperastine possesses dual activity. It also acts as a mild bronchorelaxant and has antihistaminic activity, without acting on the central nervous system or the respiratory center.

Tetrapeptide-15 (Endomorphin-2) is an endogenous agonist at μ-opioid receptors (μORs) in the spinal cord; it exhibits antinociceptive/analgesic, immunosuppressive, and pro-angiogenic activities. Endomorphin-2 increases pain thresholds in animal models of thermal pain and inhibits the formation of antibodies in other cellular models. In HUVECs, this peptide stimulates proliferation, migration, adhesion, and tube formation.

Pimethixene is an antihistamine exerting sedative and antitussive properties. Pimethixene displayed high affinity to serotonin 5-HT2A and 2B, histamine H1 and muscarinic acetylcholine M2 receptors. Oral pimethixene used to calm dry cough and irritation coughs in children.

Dibunate (also known as Becantex, Becantyl, Linctussal, L-1633, and described as the 2,6-isomer or the 2,7-isomer) is an antitussive oral medication that was used in many counties all over the world. The current marketing status of the drug is unknown and is supposed to be "discontinued".

Butamirate (or brospamin) is a medicine used for the symptomatic treatment of non-productive (dry) cough. Butamirate is centrally acting cough suppressant which is neither chemically nor pharmacologically related to opium alkaloids. In addition to its antitussive effect, Butamirate also decreases the airway resistance. Butamirate is rapidly and completely absorbed after oral administration. Maximum concentration is reached within 9 hours with sustain release tablet. Butamirate is extremely protein bound and Plasma elimination half-life is about 13 hours. Butamirate is indicated in acute cough of any etiology, pre and post operative cough sedation for surgical procedure and bronchoscopy. Butamirate is well tolerated. In rare cases, skin rash, nausea, diarrhea, dizziness have been reported.They disappear after reduction of the dosage or discontinuation of the drug.

Drotebanol is an opioid drug developed in Japan and used for the treatment of cough under the name Metebanyl, although it is now no longer used. Drotebanol possess CNS activity and is considered to be narcotic in many countries.

Butetamate is a cough suppressant. It exerts antispasmodic, bronchodilator and anticholinergic properties.