Which body organ filters drugs, alcohol, and toxins from the blood?

The liver is the primary organ responsible for filtering drugs, alcohol, and toxins from the blood. It plays a crucial role in metabolizing various substances that enter the body, breaking them down into less harmful components or preparing them for excretion. The process of detoxification occurs in the liver cells, which contain enzymes specifically designed to handle these substances.

The liver's structure allows it to receive blood from both the digestive system and the systemic circulation, making it ideally situated to process a variety of chemicals before they can impact the rest of the body. This filtering and metabolic activity helps maintain homeostasis and prevent the accumulation of potentially harmful substances in the bloodstream.

Other organs like the kidneys do play a role in excretion of waste products and balancing fluid and electrolytes but are not primarily involved in the metabolism of drugs and toxins to the same extent as the liver. The heart's primary function is to pump blood throughout the body and is not involved in filtration processes. The lungs also have a role in gas exchange and removing carbon dioxide from the blood, but they do not filter drugs or toxins in the same way. Thus, the liver is the correct choice as it directly engages in the detoxification of blood.