It is one of the most widely used medications globally, with an estimated 40,000 tonnes (44,000 tons) (50 to 120 billion pills) consumed each year, and is on the World Health Organizations List of Essential Medicines. In 2020, it was the 36th most commonly prescribed medication in the United States, with more than 17 million prescriptions. Brand vs. generic name
In 1897, scientists at the Bayer company began studying acetylsalicylic acid as a less-irritating replacement medication for common salicylate medicines. : 69–75  By 1899, Bayer had named it "Aspirin" and sold it around the world.Aspirins popularity grew over the first half of the 20th century, leading to competition between many brands and formulations. The word Aspirin was Bayers brand name; however, their rights to the trademark were lost or sold in many countries. The name is ultimately a blend of the prefix a(cetyl) + spir Spiraea, the meadowsweet plant genus from which the acetylsalicylic acid was originally derived at Bayer + -in, the common chemical suffix. Chemical properties
Aspirin decomposes rapidly in solutions of ammonium acetate or the acetates, carbonates, citrates, or hydroxides of the alkali metals. It is stable in dry air, but gradually hydrolyses in contact with moisture to acetic and salicylic acids. In solution with alkalis, the hydrolysis proceeds rapidly and the clear solutions formed may consist entirely of acetate and salicylate.Like flour mills, factories producing aspirin tablets must control the amount of the powder that becomes airborne inside the building, because the powder-air mixture can be explosive.
Pediculosis is an infestation of lice from the sub-order Anoplura, family Pediculidae. Accordingly, the infestation with head lice is named pediculosis capitis, while this with body lice, pediculosis corporis. Although pediculosis in humans may properly refer to lice infestation of any part of the body, the term is sometimes used loosely to refer to pediculosis capitis, the infestation of the human head with the specific head louse. Classification
Pediculosis may be divided into the following types:: 446–8 
Pediculosis capitis (Head lice infestation)
Pediculosis corporis (Body louse infestation, also known as Pediculosis vestimenti, Vagabonds disease)
Pediculosis pubis (Pubic louse infestation, also known as phthiriasis)

Head lice
Presentation
Head-lice infestation is most frequent on children aged 3–10 and their families. Approximately 3% of school children in the United States contract head lice. Females aged 3–12 years are most commonly infested. Those of African descent rarely experience infestation due to differences in hair texture.Head lice are spread through direct head-to-head contact with an infested person. From each egg or "nit" may hatch one nymph that will grow and develop to the adult louse. Lice feed on blood once or more often each day by piercing the skin with their tiny needle-like mouthparts. While feeding they excrete saliva, which irritates the skin and causes itching. Lice cannot burrow into the skin. Diagnosis
To diagnose infestation, the entire scalp should be combed thoroughly with a louse comb and the teeth of the comb should be examined for the presence of living lice after each time the comb passes through the hair.