From PETA's website: 

 

Every year, millions of animals are poisoned and killed in barbaric tests that were crudely developed as long ago as the 1920s to evaluate the toxicity of consumer products and their ingredients. Rats, mice, guinea pigs, rabbits, and other animals are forced to swallow or inhale massive quantities of a test substance or endure the pain of having a chemical eat away at their sensitive eyes and skin––even though the results of animal tests are often unreliable or not applicable to humans. 

 

Acute Toxicity Tests
To determine the toxic consequences of a single, short-term exposure to a product or chemical, the substance is administered to animals (usually rodents) in extremely high doses via force-feeding, forced inhalation, and/or absorption through the skin. Animals in the highest-dose groups may endure severe abdominal pain, diarrhea, convulsions, seizures, paralysis, and bleeding from the nose, mouth, and genitals before they ultimately die.1

Acute toxicity testing began during the World War I era with the now-infamous lethal dose 50 percent (LD50) test, which, even today, remains the most common form of animal-poisoning study. In this test, groups of animals are force-fed increasing amounts of a substance until 50 percent of them die.

Despite its decades of use, the LD50 test and its more contemporary adaptations have never been scientifically validated to confirm that their results are indeed predictive of chemical effects in humans. One international study that examined the results of rat and mouse LD50 tests for 50 chemicals found that these tests were able to predict toxicity in humans with only 65 percent accuracy––while a series of human cell-line tests was found to predict toxicity in humans with about 75 percent accuracy.

 

Eye- and Skin-Irritation/Corrosion Tests
The Draize eye- and skin-irritation/corrosion test dates back to the 1940s.3 During this test, rabbits are often immobilized in full-body restraints while a substance is dripped into their eyes or smeared onto their shaved skin. Laboratory technicians then record the damage, which can include inflamed skin, ulcers, bleeding, bloody scabs, swollen eyelids, irritated and cloudy eyes, or even blindness, at specific intervals for hours or days.

The scoring of eye and skin damage in the Draize test is highly subjective, and therefore, different laboratories—and even different tests within the same laboratory—often yield different results. In addition, rabbits’ eyes are anatomically and physiologically different from and tend to have stronger reactions to chemicals than humans’ eyes. In contrast, a clinical skin patch test conducted on human volunteers has been shown to produce skin-irritation data that are “inherently superior to that given by a surrogate model, such as the rabbit.

 

Product Tests 
No law requires that cosmetics and household products be tested on animals. The U.S. Food and Drug Administration (FDA) advises cosmetics manufacturers “to employ whatever testing is appropriate and effective for substantiating the safety of their products” and notes that the Federal Food, Drug, and Cosmetic Act “does not specifically require the use of animals in testing cosmetics for safety.”5 Likewise, household products regulated by the Consumer Product Safety Commission (CPSC) do not have to be tested on animals. The CPSC’s animal testing policy, as published in the Federal Register, states, “Neither the FHSA nor the Commission’s regulations requires animal testing. The FHSA and its implementing regulations only require that a product be labeled to reflect the hazards associated with that product.”

 

Tests That Are Required by Law
By contrast, lawn fertilizers, weedkillers, and household cleaners that make “germ-killing” or “antibacterial” claims on their labels are regulated as pesticides by the Environmental Protection Agency.7 By law, every pesticide must undergo dozens of separate animal tests before it can be marketed, which spells suffering and death for many animals.8 The FDA has similar testing requirements for drugs as well as chemicals that are used as additives or preservatives in processed foods.

 

Reference: (2016). Animals used for experimentation. [online]. Available from: http://www.peta.org/issues/animals-used-for-experimentation/ [Accessed 20 November 2015].