What causes fatty liver disease in humans is still being studied, but there are some factors that are known to contribute. These include alcohol abuse, hepatitis and cirrhosis, diabetes mellitus, cancer, and radiation therapy. The liver is an organ that works for the body. It stores toxins and aids in the excretion of these substances. Over time, the liver can develop blockages, which can result in liver failure or liver cancer. In addition to these reasons, there are other less known factors that may contribute to this problem. When what causes fatty liver disease in humans is not controlled, it can lead to a variety of health problems. Fatty liver does not only affect the liver, but it can affect the rest of the body. One of the most common complications from having this condition is cirrhosis of the liver. Cirrhosis is when the scar tissue builds up around the liver. This condition occurs when there is too much activity going on in the liver and it becomes overworked. When it does not get enough oxygen, the scar tissue cannot be removed and will eventually cause death. What causes fatty liver is also directly related to alcohol abuse. The more alcohol a person drinks, the more damage their liver will suffer. Alcohol use can directly cause liver damage because of the buildup of toxins in the bloodstream, specifically acetaldehyde. Acetaldehyde is a harmful chemical that can severely impair liver function. When there is too much acetaldehyde in the bloodstream, it can increase the risk of developing a form of cancer called liver cancer. Other factors may play a role in developing fatty liver disease. Overweight individuals may have an increased risk of developing this condition because their liver does not work as well as it should. People with a family history of liver disease are at a higher risk. A liver disorder called fatty liver is hereditary, meaning that if one member gets it, you could have a higher risk of getting it as well. There are other reasons that people develop fatty liver, but the main ones are alcohol abuse and genetics.