In the human body, which organ is primarily responsible for detoxifying harmful substances?

The liver is the primary organ responsible for detoxifying harmful substances in the body. It plays a central role in metabolizing drugs, alcohol, and other toxic compounds that enter the bloodstream. The liver contains specialized cells called hepatocytes, which process these substances and convert them into less harmful forms that can be easily excreted from the body. Additionally, the liver produces bile, which helps in the digestion and absorption of fats, and plays a crucial part in the elimination of waste products.

While the kidneys are also involved in detoxification, mainly through filtering waste products and excess substances from the blood to form urine, their primary role is in urine production rather than the direct metabolism of toxins. The spleen assists in filtering blood and recycling iron but is not directly involved in detoxifying harmful substances. The gallbladder functions primarily in storing bile produced by the liver, rather than detoxifying the body. Therefore, the liver is clearly the vital organ for detoxification among the options provided.