Iodide I-131 (as Sodium iodide I-131) is a radioisotopic drug used for the treatment and palliation of thyroid malignancy. Therapeutic solutions of Sodium Iodide-131 are indicated for the treatment of hyperthyroidism and thyroid carcinomas that take up iodine. Palliative effects may be observed in patients with advanced thyroid malignancy if the metastatic lesions take up iodine. It is also indicated for use in performance of the radioactive iodide (RAI) uptake test to evaluate thyroid function. Taken orally, sodium iodide I-131 is rapidly absorbed and distributed within the extracellular fluid of the body. The iodide is concentrated in the thyroid via the sodium/iodide symporter, and subsequently oxidized to iodine. The destruction of thyroidal tissue is achieved by the beta emission of sodium iodide I-131.

Dimercaprol (2, 3-dimercapto-1-propanol) or British anti-Lewisite (BAL), is a colorless or almost colorless liquid chelating agent having a disagreeable, mercaptan-like odor. Dimercaprol was developed at Oxford University during World War II as a means of treating and reversing poisoning from Lewisite, an arsenical gas used in chemical warfare (and thus initially called British anti-Lewisite [BAL]). The sulfhydryl groups of dimercaprol form complexes with certain heavy metals thus preventing or reversing the metallic binding of sulfhydryl-containing enzymes. Parenterally administered dimercaprol is used to treat arsenic, gold, copper and mercury poisoning. It is indicated in acute lead poisoning when used concomitantly with edetate clcium disodium. Dimercaprol is occasionally used in the initial treatment of severe, symptomatic Wilson disease, but generally for a short time only.

Helium is a chemical element with symbol He and atomic number 2. It is inert, non-toxic odorless gas. In medicine, helium is used to help the flow of oxygen in diseases such as bronchitis, or to assist breathing if part of lungs fails to expand. The mixture of helium and oxygen is known as heliox.

Carbon dioxide is a colorless gas occurring naturally in Earth's atmosphere. Carbon dioxide is a primary carbon source for life on Earth. It is produced by all aerobic organisms during metabolism of carbohydrates and lipids. Carbon dioxide is used in food industry as an acidity regulator and for production of carbonated soft drinks and soda water. In medicine, carbon dioxide is commonly used as an insufflation gas for minimally invasive surgery (laparoscopy, endoscopy, and arthroscopy) to enlarge and stabilize body cavities to provide better visibility of the surgical area. A mixture of carbon dioxide and oxygen is used for stimulation of breathing after apnea, in anesthetic procedures to increase the depth of respiration, to facilitate blind intubations in anesthetic practice.

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.

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.

Barium sulfate, an insoluble in water substance, which was approved under the brand name E-Z-HD for use in double-contrast radiographic examinations of the esophagus, stomach and duodenum to visualize the gastrointestinal (GI) tract in patients 12 years and older. Due to its high atomic number, barium is opaque to x-rays and therefore acts as a positive contrast agent for radiographic studies.

Elemental nitrogen is a colorless, odorless, tasteless and mostly inert diatomic gas at standard conditions, constituting 78% by volume of Earth's atmosphere. Nitrogen occurs in all living organisms. It is a constituent element of amino acids and therefore of proteins and nucleic acids (DNA and RNA). Nitrogen is found in the chemical structure of almost all neurotransmitters and is a key component of alkaloids. Specific bacteria (e. g. Rhizobium trifolium) possess nitrogenase enzymes which can fix atmospheric nitrogen into a form (ammonium ion) which is chemically useful to higher organisms. Animals use nitrogen-containing amino acids from plant sources, as starting materials for all nitrogen-compound animal biochemistry, including the manufacture of proteins and nucleic acids. Animal metabolism of NO (nitric oxide) results in production of nitrite. Animal metabolism of nitrogen in proteins generally results in excretion of urea, while animal metabolism of nucleic acids results in excretion of urea and uric acid. The characteristic odor of animal flesh decay is caused by nitrogen-containing long-chain amines, such as putrescine and cadaverine. Decay of organisms and their waste products may produce small amounts of nitrate, but most decay eventually returns nitrogen content to the atmosphere, as molecular nitrogen. The circulation of nitrogen from the atmosphere through organics and then back to the atmosphere is commonly referred to as the nitrogen cycle. Nitrogen can be measured in urine with the Kjeldahl method or by spectrophotometric methods (enzymic tests). Total urinary nitrogen is calculated based on urea urinary nitrogen quantified with these methods. Liquid nitrogen (E941) is widely used in food industry as a freezing agent and as a protection against the impact of microorganisms. Nitrogen (E941) extends the period of validity of food and maintains its nutrients and is also used for packing products. In other fields of industry, nitrogen (E941) is useful in suppressing the combustion processes and in creating protective environment in order to avoid oxidation. Medical nitrogen has various medical uses, especially in liquid form when it provides temperatures as low as -196° C. Applications of medical nitrogen in the healthcare environment may include the following: * In cryopreservation for the long-term preservation of blood, blood components, other cells, body fluids or tissue samples. * In cryosurgery for minor surgical procedures in dermatology. * As a component in many gas mixtures. * As a displacement medium for sterile equipment, a non-oxidising displacement medium in pharmaceutical vials and as a propellant in pressurised aerosol dispensers. * As a source of pneumatic pressure to power gas-operated medical devices. * As a coolant for carbon dioxide surgical lasers.

Oxygen is a chemical element with atomic number 8. Diatomic oxygen constitutes 20.8% of the Earth's atmosphere. Diatomic oxygen is used by complex life forms such as animals, in cellular respiration. Medical oxygen is widely used in clinical practice to provide a basis for most modern anaesthetic techniques; to restore the tissue oxygen tension towards normal by improving oxygen availability in a wide range of conditions such as shock, severe haemorrhage, coronary occlusion, carbon monoxide poisoning, major trauma; to aid the resuscitation of the critically ill, when the circulation is impaired; to aid in neonatal resuscitation; to treat acute severe headache in adults diagnosed with cluster headache.

Alcohols exhibit rapid broad-spectrum antimicrobial activity against vegetative bacteria (including mycobacteria), viruses, and fungi but are not sporicidal. They are, however, known to inhibit sporulation and spore germination, but this effect is reversible. Because of the lack of sporicidal activity, alcohols are not recommended for sterilization but are widely used for both hard-surface disinfection and skin antisepsis. Lower concentrations may also be used as preservatives and to potentiate the activity of other biocides. Many alcohol products include low levels of other biocides (in particular chlorhexidine), which remain on the skin following evaporation of the alcohol, or excipients (including emollients), which decrease the evaporation time of the alcohol and can significantly increase product efficacy. Ethanol in combination with: chlorhexidine gluconate 1% was approved to use in surgical hand antiseptic. It significantly reduces the number of microorganisms on the hands and forearms prior to surgery or patient care. Ethanol is also used as a co-solvent to dissolve many insoluble drugs and to serve as a mild sedative in some medicinal formulations. Ethanol is metabolized by the hepatic enzyme alcohol dehydrogenase. Ethanol affects the brain’s neurons in several ways. It alters their membranes as well as their ion channels, enzymes, and receptors. Alcohol also binds directly to the receptors for acetylcholine, serotonin, GABA, and the NMDA receptors for glutamate. The sedative effects of ethanol are mediated through binding to GABA receptors and glycine receptors (alpha 1 and alpha 2 subunits). It also inhibits NMDA receptor functioning. In its role as an anti-infective, ethanol acts as an osmolyte or dehydrating agent that disrupts the osmotic balance across cell membranes.