Benzyl Alcohol is an aromatic alcohol used in a wide variety of cosmetic formulations as a fragrance component, preservative, solvent, and viscosity-decreasing agent. FDA agency approved benzyl alcohol for the treatment of head lice. The drug acts on head lice by inhibiting them from closing their respiratory spiracles, allowing the vehicle to obstruct the spiracles and causing the lice to asphyxiate.

Benzyl benzoate is an organic compound with the formula C6H5CH2O2CC6H5. It is the ester of benzyl alcohol and benzoic acid. It forms either a viscous liquid or solid flakes and has a weak, sweet-balsamic odor. It occurs in a number of blossoms (e. g. tuberose, hyacinth) and is a component of Balsam of Peru and Tolu balsam. It is on the World Health Organization's List of Essential Medicines, a list of the most important medication needed in a basic health system. Benzyl benzoate is one of the older preparations used to treat scabies. Scabies is a skin infection caused by the mite sarcoptes scabiei. It is characterised by severe itching (particularly at night), red spots, and may lead to a secondary infection. Benzyl benzoate is lethal to this mite and so is useful in the treatment of scabies. It is also used to treat lice infestation of the head and body. Benzyl benzoate is not the treatment of choice for scabies due to its irritant properties. Benzyl benzoate exerts toxic effects on the nervous system of the parasite, resulting in its death. It is also toxic to mite ova, though its exact mechanism of action is unknown. In vitro, benzyl benzoate has been found to kill the Sarcoptes mite within 5 minutes.

Metronidazole was synthesized by France's Rhone-Poulenc laboratories and introduced in the mid-1950s under the brand name Flagel in the US, while Sanofi-Aventis markets metronidazole globally under the same trade name, Flagyl, and also by various generic manufacturers. Metronidazole is one of the rare examples of a drug developed as ant parasitic, which has since gained broad use as an antibacterial agent. Metronidazole, a nitroimidazole, exerts antibacterial effects in an anaerobic environment against most obligate anaerobes. Metronidazole is indicated for the treatment of the following infections due to susceptible strains of sensitive organisms: Trichomoniasis: symptomatic, asymptomatic, asymptomatic consorts; Amebiasis: acute intestinal amebiasis (amebic dysentery) and amebic liver abscess; Anaerobic bacterial infections; Intra-abdominal infections, including peritonitis, intra-abdominal abscess, and liver abscess; Skin and skin structure infections; Gynecologic infections, including endometritis, endomyometritis, tubo-ovarian abscess, and postsurgical vaginal cuff infection; Bacterial septicemia; Bone and joint infections, as adjunctive therapy; Central Nervous System infections, including meningitis and brain abscess; Lower Respiratory Tract infections, including pneumonia, empyema, and lung abscess; Endocarditis. Metronidazole is NOT effective for infections caused by aerobic bacteria that can survive in the presence of oxygen. Metronidazole is only effective against anaerobic bacterial infections because the presence of oxygen will inhibit the nitrogen-reduction process that is crucial to the drug's mechanism of action. Once metronidazole enters the organism by passive diffusion and activated in the cytoplasm of susceptible anaerobic bacteria, it is reduced; this process includes intracellular electron transport proteins such as ferredoxin, transfer of an electron to the nitro group of the metronidazole, and formation of a short-lived nitroso free radical. Because of this alteration of the metronidazole molecule, a concentration gradient is created and maintained which promotes the drug’s intracellular transport. The reduced form of metronidazole and free radicals can interact with DNA leading to inhibition of DNA synthesis and DNA degradation leading to death of the bacteria. The precise mechanism of action of metronidazole is unknown. Metronidazole has a limited spectrum of activity that encompasses various protozoans and most Gram-negative and Gram-positive anaerobic bacteria. Metronidazole has activity against protozoans like Entamoeba histolytica, Giardia lamblia and Trichomonas vaginalis, for which the drug was first approved as an effective treatment.