Excessive alcohol consumption can lead to catastrophic health consequences. Heavy drinking increases the risk of injury, spousal or child abuse, risky sexual behavior and serious medical consequences such as alcoholic liver disease, hypertension and gastrointestinal cancer. Chronic excessive alcohol consumption can be particularly damaging to the brain, increasing the risk of dementia, stroke and mental disorders. However, moderate alcohol consumption has many health benefits and is good for the brain. The U.S. Food and Drug Administration (FDA) defines “moderate drinking” as <1 standard glass of alcohol per day for women and <2 standard glasses of alcohol for men. In the United States, a standard glass is 12 grams of ethanol, which is equivalent to 12 ounces of regular beer, 5 ounces of 12 proof wine, and 1.2 ounces of distilled spirits. A recent survey from the Substance Abuse and Mental Health Administration (SAMHSA) showed that roughly 86.8 percent of people over the age of 18 have had a drink in their lifetime, and 57 percent said they had most recently consumed alcohol in the last month. Nearly 1 in 4 adults surveyed reported having consumed alcohol in the past month, that is, 4 (women) or 5 (men) standard glasses of alcohol in 2 hours. About 7 percent of people have an alcohol use disorder. A study from Columbia University showed that drinking is worse, reporting that 3 out of 10 Americans may have a drinking problem or have abused alcohol at some point in the past. According to the National Center for Disease Control and Prevention (CDC), excessive alcohol consumption is a significant cause of nearly 90,000 deaths in the United States each year and is the third leading cause of lifestyle-related deaths. No amount of alcohol is safe to drink, according to the 2014 World Health Organization World Cancer Report, which details the dose-dependent relationship between alcohol consumption and tumors of the mouth, throat, esophagus, colorectum, liver, breast and pancreas. Other studies have shown that women with high risk factors for breast cancer who drink alcohol will significantly increase the density of mammography. The relationship between alcohol and the brain is complex. Many studies have shown that light to moderate alcohol consumption can prevent cardiovascular disease, an effect that can be attributed to ethanol itself and to polyphenols, which have antioxidant effects. Red wine has the most benefits, while the benefits of beer, especially stout, are only legendary. Alcohol consumption has also been reported to have atherosclerosis prevention and anti-inflammatory effects, improving cholesterol status, platelet coagulation and insulin sensitivity, all of which can have neurological benefits. Light to moderate alcohol consumption is also thought to be associated with lower ischemic and hemorrhagic strokes. However, heavy alcohol consumption increases the risk of hemorrhagic stroke and more severe ischemic cerebrovascular events. It should be noted that many of the studies examining the effects of ethanol on the cardiovascular system are observational and the investigators have not demonstrated a causal relationship. While moderate alcohol consumption also reduces the risk of dementia, the cognitive damage of excessive alcohol consumption is severe. a study published in January 2014 in Neurology showed that middle-aged adults who drank more than 2.5 standard glasses of alcohol per day had a higher risk of overall cognitive decline (especially memory) within 10 years. Notably, animal studies have shown that fish oil may have a protective effect by slowing neuronal degeneration caused by ethanol. Of greatest concern to society at large and the medical community is the effect of alcohol on the brains of children and adolescents, and a Swedish study published in August 2013 in the journal JAMA Internal Medicine reported that alcoholism was the most significant of the nine influences leading to dementia episodes in young patients. In addition, MRI findings in 2012 found that children born to mothers who drank heavily during pregnancy had significantly reduced brain plasticity compared to other children. Not only are certain patients with mental illnesses more likely to experience alcohol and substance abuse, excessive alcohol consumption can also lead to mental illness, with about 1/3 of alcoholics suffering from mental illness. Alcohol is known to have considerable psychosocial effects, including increased risk of legal disputes, social and occupational impairment, domestic violence, and high risk of suicide. The psychiatric manifestations of alcohol may be mediated in part by its effects on neurotransmitter function, particularly loss of serotonergic function. a 2012 study found that women were far more susceptible than men to serotonergic disorders caused by excessive alcohol consumption. As with most substance abuse, alcohol increases dopamine production in the limbic reward circuit of the central cortical branch. In social drinkers, subjective intoxication by intravenous ethanol activates reward circuits, including the vomeronasal nucleus. This activation process causes a decrease in subjective pleasure and response to fear-based stimuli. In severe alcoholics, the activation of the voxel nucleus is more delayed by alcohol consumption, suggesting a reduced pleasure response. When social drinkers make risky choices, ethanol enhances voxel activation and decreases responses to positive or negative outcomes in the striatum, thalamus, and insula. Thus, under the influence of ethanol, the risky behavior itself is more rewarding and the outcome is less important. The effects of ethanol on the brain are complex, with both acute and chronic effects, involving multiple systems, and varying widely by age and genetic factors. Moderate alcohol consumption can benefit the brain; however, the damage caused by mental, neurological, and other somatic conditions associated with alcohol consumption may instantly outweigh the benefits. Therefore, physicians should be concerned about the effects of alcohol abuse on the brain and general health and promote screening for alcohol abuse. As the ancient Greek proverb says, "Never overdo everything."