Histamine is a depressor amine derived by enzymatic decarboxylation of histidine. It is a powerful stimulant of gastric secretion, a constrictor of bronchial smooth muscle, a vasodilator, and a centrally acting neurotransmitter. Phosphate salt of jistamine was used as a diagnostic aid for evaluation of gastric acid secretory function. In addition, this compound is used as a positive control in evaluation of allergenic (immediate hypersensitivity or "Type I") skin testing. In addition, histamine is being studied for treatment of multiple sclerosis. It was approved, that histamine physiological functions are mediated by four 7-transmembrane G protein-coupled receptors (H1R, H2R, H3R, H4R) that are all targets of pharmacological intervention. The receptors display molecular heterogeneity and constitutive activity. H1R antagonists are long known antiallergic and sedating drugs, whereas the H2R led to the development of H2R-antagonists that revolutionized stomach ulcer treatment. The H3R is an auto receptor and heteroreceptor providing negative feedback on histaminergic and inhibition on other neurons. The H4R occurs on immuncompetent cells and the development of anti-inflammatory drugs is anticipated.

Algeldrate (Aluminium hydroxide) is the amphoteric inorganic compound used as an antacid in the treatment of Duodenal, Peptic and Stomach Ulcer and some other conditions. Aluminium hydroxide is preferred over other alternatives such as sodium bicarbonate because Al(OH)3, being insoluble, does not increase the pH of stomach above 7 and hence, does not trigger secretion of excess acid by the stomach. Brand names include Alu-Cap, Aludrox, Gaviscon or Pepsamar. It reacts with the excess acid in the stomach, reducing the acidity of the stomach content, which may relieve the symptoms of ulcers, heartburn or dyspepsia. Such products can cause constipation, because the aluminum ions inhibit the contractions of smooth muscle cells in the gastrointestinal tract, slowing peristalsis and lengthening the time needed for stool to pass through the colon. Some such products (such as Maalox) are formulated to minimize such effects through the inclusion of equal concentrations of magnesium hydroxide or magnesium carbonate, which have counterbalancing laxative effects. This compound is also used to control phosphate (phosphorus) levels in the blood of people suffering from kidney failure. Precipitated aluminum hydroxide is included as an adjuvant in some vaccines (e.g. anthrax vaccine). One of the well-known brands of aluminum hydroxide adjuvant is Alhydrogel, made by Brenntag Biosector. Since it absorbs protein well, it also functions to stabilize vaccines by preventing the proteins in the vaccine from precipitating or sticking to the walls of the container during storage. Aluminium hydroxide is sometimes mistakenly called "alum", which properly refers to aluminum potassium sulfate. Vaccine formulations containing aluminum hydroxide stimulate the immune system by inducing the release of uric acid, an immunological danger signal. This strongly attracts certain types of monocytes which differentiate into dendritic cells. The dendritic cells pick up the antigen, carry it to lymph nodes, and stimulate T cells and B cells. It appears to contribute to induction of a good Th2 response, so is useful for immunizing against pathogens that are blocked by antibodies. In the 1960s and 1970s, it was speculated that aluminum was related to various neurological disorders including Alzheimer's disease. Since then, multiple epidemiological studies have found no connection between exposure to aluminum and neurological disorders.

Methyl salicylate (or methyl 2-hydroxybenzoate), also known as wintergreen oil, is a natural product and is present in white wine, tea, porcini mushroom Boletus edulis, Bourbon vanilla, clary sage, red sage and fruits including cherry, apple, raspberry, papaya and plum. Methyl salicylate is topically used in combination with methanol and under brand name SALONPAS to temporarily relieves mild to moderate aches and pains of muscles and joints associated with: strains, sprains, simple backache, arthritis, bruises. The precise mechanism of action of methyl salicylate is not known, but there is suggested, that it cause dilation of the capillaries thereby increasing blood flow to the area.

Naronapride (ATI-7505), an orally administered, cisapride analogue and serotonin4 (5HT4) receptor agonist, is being developed by Renexxion for the treatment of multiple gastrointestinal disorders. Sinovant is initially developing naronapride for the treatment of irritable bowel syndrome – constipation (IBS-C), a disease that affects millions of Chinese patients and for which few effective treatment options are available. Naronapride has been evaluated in over 900 subjects in multiple randomized controlled clinical studies and has demonstrated promising results in patients with gastroesophageal reflux disease (GERD), erosive esophagitis (EE), and chronic idiopathic constipation (CIC). Naronapride’s low systemic absorption and high specificity for 5HT4 and D2 receptors is thought to improve its safety and tolerability profile relative to other members of the class.