In vivo testing refers to experiments or studies that are conducted using living organisms, such as animals or humans, to evaluate the safety, efficacy, or pharmacokinetics of a drug or medical treatment.

In vivo testing can provide valuable information about how a drug or treatment behaves in a living organism, including its absorption, distribution, metabolism, and excretion. Animal studies are often used in the early stages of drug development to test the safety and efficacy of a new compound, and to identify potential adverse effects.

Human clinical trials are the most common form of in vivo testing in drug development. These studies involve testing a new drug or treatment on human volunteers to evaluate its safety, efficacy, and side effects. Clinical trials are typically conducted in phases, with each phase designed to answer specific questions about the drug’s safety and effectiveness.

In vivo testing is an important part of the drug development process, but it must be conducted ethically and in compliance with regulatory guidelines. Animal studies, in particular, have come under scrutiny in recent years due to concerns about animal welfare and the reliability of animal models in predicting human outcomes. As such, alternative testing methods, such as in vitro (cell-based) and in silico (computer-based) models, are being developed to supplement or replace animal testing where possible.