Nitrite Ion is a symmetric anion with equal N–O bond lengths. Nitrite is important in biochemistry as a source of the potent vasodilator nitric oxide. Nitrate or nitrite (ingested) under conditions that result in endogenous nitrosation has been classified as "Probably carcinogenic to humans" (Group 2A) by International Agency for Research on Cancer (IARC), the specialized cancer agency of the World Health Organization (WHO) of the United Nations. Sodium nitrite is used for the curing of meat because it prevents bacterial growth and, as it is a reducing agent (opposite of oxidation agent), in a reaction with the meat's myoglobin, gives the product a desirable pink-red "fresh" color, such as with corned beef. This use of nitrite goes back to the Middle Ages, and in the US has been formally used since 1925. Because of the relatively high toxicity of nitrite (the lethal dose in humans is about 22 milligrams per kilogram of body weight), the maximum allowed nitrite concentration in meat products is 200 ppm. At these levels, some 80 to 90% of the nitrite in the average U.S. diet is not from cured meat products, but from natural nitrite production from vegetable nitrate intake. Under certain conditions – especially during cooking – nitrites in meat can react with degradation products of amino acids, forming nitrosamines, which are known carcinogens. However, the role of nitrites (and to some extent nitrates) in preventing botulism by preventing C. botulinum endospores from germinating have prevented the complete removal of nitrites from cured meat, and indeed by definition in the U.S., meat cannot be labeled as "cured" without nitrite addition. They are considered irreplaceable in the prevention of botulinum poisoning from consumption of cured dry sausages by preventing spore germination. Nitrite is a member of the drug class antidotes and is used to treat Cyanide Poisoning.

Methylene blue, also known as methylthioninium chloride, is a medication from WHO's list of essential medicines. Upon administration, methylene blue is converted to leukomethylene blue by erythrocyte methemoblobin reductase in the presence of NADPH. Leukomethylene blue than reduces methemoglobin to oxyhemoglobin, thus restoring oxygen carrying capacity of the blood. Methylene blue is also used as a dye for various diagnostic procedures, for treatment of ifosfamide toxicity and for in vitro staining. Historically, it was used as a photosensitizer for photodynamic therapy for topical treatment of dermatologic or mucocutaneous infections, as an antidote for cyanide poisoning, but these applications are no longer approved. Methylene blue is investigated in clinical trials for treatment of septic shock and Alzheimer's disease.

There is no information about biological and pharmacological application of Iron(II) fluoride (also known as ferrous fluoride). It is known, that this substance is used to catalyze some organic reactions.

There is no information about biological and pharmacological application of Iron(II) fluoride (also known as ferrous fluoride). It is known, that this substance is used to catalyze some organic reactions.

Acetic acid (a component of vinagre) is used in medicine for the treatment of otitis externa caused by bacterial infections. The solution containing acetic acid was approved by FDA.

Pilocarpine is an alkaloid extracted from plants of the genus Pilocarpus. The drug stimulates the muscarinic receptors (especially M3, which is expressed in smooth muscles and glands) and thus induces salivation, hypertension and water intake. Pilocarpine was appoved by FDA for the alleviation of symptoms of xerostomia in patients who have undergone radiation therapy to their head and neck cancer and in patients with Sjogren's Syndrome. Ophthalmic solution of the drug is prescribed for the treatment of glaucoma, ocular hypertension, postoperative elevated intraocular pressure, etc.

Quinine soluble salts possess the extremely bitter taste, that may have a perplexing problem especially to children. That is why the most common combinations which are administered in this way are the sulphate, salicylate, tannate and certain esters. Quinine tannate, an insoluble quinine salt has been known in medicine for a very long time. However, many experiments have revealed that quinine tannate was practically inert as a medicinal substance.

Quinine soluble salts possess the extremely bitter taste, that may have a perplexing problem especially to children. That is why the most common combinations which are administered in this way are the sulphate, salicylate, tannate and certain esters. Quinine tannate, an insoluble quinine salt has been known in medicine for a very long time. However, many experiments have revealed that quinine tannate was practically inert as a medicinal substance.

Since its discovery as component of the tea leaf by Albert Kossel in 1888, the history of theophylline (CAS 58-55-9) has been a long and successful one. At the turn of the century, theophylline became less expensive due to chemical synthesis and was primarily used as diuretic in subsequent years. It was Samuel Hirsch who discovered the bronchospasmolytic effect of theophylline in 1992, however, despite this pioneering discovery theophylline continued to be used primarily as diuretic and cardiac remedy. The molecular mechanism of bronchodilatation is inhibition of phosphodiesterase(PDE)3 and PDE4, but the anti-inflammatory effect may be due to histone deacetylase (HDAC) activation, resulting in switching off of activated inflammatory genes. Theophylline is indicated for the treatment of acute exacerbations of the symptoms and reversible airflow obstruction associated with asthma and other chronic lung diseases, e.g., emphysema and chronic bronchitis.

Acetic acid (a component of vinagre) is used in medicine for the treatment of otitis externa caused by bacterial infections. The solution containing acetic acid was approved by FDA.