Maximum Tolerated Dose (MTD) refers to the highest dose or level of a substance that can be administered to a living organism, such as a human or animal, without causing an unacceptable level of toxicity or harm. It is typically determined through pre-clinical studies and toxicological testing using animal models, with the goal of establishing safe and effective dosages for use in human or animal subjects.

In the healthcare industry, MTD is an important concept in drug development and clinical trials, as it helps to establish safe dosages for pharmaceutical products. It is also used in radiation therapy, where MTD is used to determine the maximum amount of radiation a patient can safely receive without causing significant harm. In addition, MTD is used in the study of environmental toxicology to determine the safety of various chemicals and substances in the environment.

Overall, MTD is an important tool for ensuring the safety and efficacy of pharmaceutical products, as well as protecting human and animal health in the face of potential environmental toxic exposures.