An acid attack, also called acid throwing, vitriol attack, or vitriolage, is a form of violent assault involving the act of throwing acid or a similarly corrosive substance onto the body of another "with the intention to disfigure, maim, torture, or kill". Perpetrators of these attacks throw corrosive liquids at their victims, usually at their faces, burning them, and damaging skin tissue, often exposing and sometimes dissolving the bones. Acid attacks can lead to permanent, partial or complete blindness.

The most common types of acid used in these attacks are sulfuric and nitric acid. Hydrochloric acid is sometimes used but is much less damaging. Aqueous solutions of strongly alkaline materials, such as caustic soda (sodium hydroxide) or ammonia, are used as well, particularly in areas where strong acids are controlled substances.

The long-term consequences of these attacks may include blindness, as well as eye burns, with severe permanent scarring of the face and body, along with far-reaching social, psychological, and economic difficulties.

Although acid attacks occur all over the world, this type of violence is most common in developing regions, It is often a form of gender-based violence, with "a disproportionate impact on women" according to Acid Survivors Trust International (ASTI). However, in countries such as the United Kingdom where acid attacks are associated primarily with gang violence, the majority of both perpetrators and victims are male.

The most notable effect of an acid attack is the lifelong bodily disfigurement. According to the Acid Survivors Foundation in Bangladesh, there is a high survival rate amongst victims of acid attacks. Consequently, the victim is faced with physical challenges, which require long-term surgical treatment, as well as psychological challenges, which require in-depth intervention from psychologists and counselors at each stage of physical recovery. These far-reaching effects on their lives impact their psychological, social, and economic viability in communities.

The medical effects of acid attacks are extensive. As a majority of acid attacks are aimed at the face, several articles thoroughly reviewed the medical implications for these victims. The severity of the damage depends on the concentration of the acid and the time before the acid is thoroughly washed off with water or neutralized with a neutralizing agent. The acid can rapidly eat away skin, the layer of fat beneath the skin, and in some cases even the underlying bone. Eyelids and lips may be completely destroyed and the nose and ears severely damaged. Though not exhaustive, Acid Survivors Foundation Uganda findings included:

In addition to these above-mentioned medical effects, acid attack victims face the possibility of sepsis, kidney failure, skin depigmentation, and even death.

A 2015 attack that involved throwing sulfuric acid on a man's face and body while he lay in bed caused him, among other serious injuries, to become paralyzed from the neck down.