Antimicrobial ingredients are materials that protect against the growth of microorganisms in personal care products, including bacteria, viruses and fungi. Antimicrobial ingredients can also kill organisms that may be present in ingredients that may be used to make products.

Antimicrobial personal care products, which are sometimes referred to as antibacterial products, provide an important extra measure of protection for consumers at home and doctors and nurses in hospitals seeking to prevent spread of germs. These products, depending on their formulation and application, kill or inhibit the growth of bacteria that cause skin infections, intestinal illnesses or other commonly transmitted diseases. These include potentially fatal illnesses caused by bacteria such as Salmonella and E. coli.

Acne is a common skin disease that causes pimples. Pimples form when hair follicles under your skin clog up. Most pimples form on the face, neck, back, chest, and shoulders. Anyone can get acne, but it is common in teenagers and young adults. It is not serious, but it can cause scars.

No one knows exactly what causes acne. Hormone changes, such as those during the teenage years and pregnancy, probably play a role. There are many myths about what causes acne. Another common myth is that dirty skin causes acne; however, blackheads and pimples are not caused by dirt. Stress doesn't cause acne, but stress can make it worse.

Dandruff is the shedding of dead skin cells from the scalp. As skin cells die a small amount of flaking is normal; about 487,000 cells/cm² get released normally after detergent treatment. Some people, however, experience an unusually large amount of flaking either chronically or as a result of certain triggers, up to 800,000 cells/cm², which can also be accompanied by redness and irritation.

Dandruff is a common scalp disorder affecting almost half of the population at the post-pubertal age and of any gender and ethnicity. It often causes itching. It has been well established that keratinocytes play a key role in the expression and generation of immunological reactions during dandruff formation. The severity of dandruff may fluctuate with season as it often worsens in winter

Dandruff can have several causes, including simple dry skin, irritated, oily skin, not shampooing often enough, psoriasis, eczema, Sensitivity to hair care products, or a yeast-like fungus.

Simple dry skin is the most common cause of flaking dandruff.

As the epidermal layer continually replaces itself, cells are pushed outward where they eventually die and flake off. For most individuals, these flakes of skin are too small to be visible. However, certain conditions cause cell turnover to be unusually rapid, especially in the scalp. It is hypothesized that for people with dandruff, skin cells may mature and be shed in 2 7 days, as opposed to around a month in people without dandruff. The result is that dead skin cells are shed in large, oily clumps, which appear as white or grayish patches on the scalp, skin and clothes.

Body odor is present in animals including humans, and its intensity can be influenced by many factors (behavioral patterns, survival strategies). Body odor has a strong genetic basis both in animals and humans, but it can be also strongly influenced by various diseases and psychological conditions.

In humans, the formation of body odors is mainly caused by skin glands excretions and bacterial activity. Between the different types of skin glands, the human body odor is primarily the result of the apocrine sweat glands, which secrete the majority of chemical compounds needed for the skin flora to metabolize it into odorant substances. This happens mostly in the axillary (armpit) region, although the gland can also be found in the areola, anogenital region, and around the navel. In humans the armpit regions seem more important than the genital region for body odor which may be related to human bipedalism. The genital and armpit regions also contain springy hairs which help diffuse body odors.

Body odor is influenced by the actions of the skin flora, including members of Corynebacterium, which manufacture enzymes called lipases that break down the lipids in sweat to create smaller molecules like butyric acid. These smaller molecules smell, and give body odor its characteristic aroma. Propionic acid (propanoic acid) is present in many sweat samples. This acid is a breakdown product of some amino acids by propionibacteria, which thrive in the ducts of adolescent and adult sebaceous glands. Because propionic acid is chemically similar to acetic acid with similar characteristics including odor, body odors may be identified as having a vinegar-like smell by certain people. Isovaleric acid (3-methyl butanoic acid) is the other source of body odor as a result of actions of the bacteria Staphylococcus epidermidis, which is also present in several strong cheese types.

Athlete's foot (also known as ringworm of the foot, tinea pedis, and moccasin foot) is a fungal infection of the skin that causes scaling, flaking, and itch of affected areas, and in severe cases, swelling and amputation of the foot. It is caused by fungi in the genus Trichophyton. The disease is typically transmitted in moist communal areas where people walk barefoot, such as showers or bathhouses,[citation needed] and requires a warm moist environment, such as the inside of a shoe, in order to incubate.

Although the condition typically affects the feet, it can infect or spread to other areas of the body, including the groin, particularly areas of skin that are kept hot and moist, such as with insulation, body heat, and sweat, e.g. in a shoe, for long periods of time. While the fungus is generally picked up through walking barefoot in an infected area or using an infected towel, infection can be prevented by remaining barefoot as this allows the feet to dry properly and removes the fungus' primary incubator - the warm moist interior of a shoe. Athlete's foot can be treated by a very limited number of pharmaceuticals (including creams) and other treatments, although it can be almost completely prevented by never wearing shoes, or wearing them as little as possible.

Bacterial vaginosis (BV) or very uncommonly vaginal bacteriosis is a disease of the vagina caused by bacteria. According to the U.S. Centers for Disease Control and Prevention (CDC), risk factors for BV include douching and having new or multiple sex partners, although it is unclear what role sexual activity plays in the development of BV. BV is caused by an imbalance of naturally occurring bacterial flora and is often confused with yeast infection (candidiasis) or infection with Trichomonas vaginalis (trichomoniasis), which are not caused by bacteria.