This article summarizes the recommended maximum intake (or safe limits) of the drug alcohol, to be specific ethanol, as recommended by the health agencies of various governments. These recommendations are varied, reflecting scientific uncertainty. The recommendations as to the recommended maximum intake are distinct from legal restrictions (e.g. on driving) that may apply in those countries.
The guidelines are general guidelines applying to a typical person. However, there are some people who should not consume alcohol, or limit their use to less than guideline amounts. These are:
"People with chronic hepatitis C (or other forms of chronic hepatitis infection) who drink heavily [and exceed maximum recommended consumption levels] have poorer health outcomes than those who drink less." That is, they have poorer health outcomes than do those who drink within the guidelines.
Thin people — those below average body weight (60 kilograms (130 lb) for men, 50 kilograms (110 lb) for women)
People with a relative who has, or has had, a problem with alcohol. First-degree relatives are parents and siblings; second-degree relatives are grandparents, uncles, aunts, and cousins. These individuals "are urged to be careful about how much they drink."
People with a mental health problem (such as anxiety or depression) or sleep disturbances  Individuals with a mental health problem "should take particular care to stay within the levels set in Guideline 1" (i.e. no more than 2 standard drinks a day).
People taking medications or other drugs, if contraindicated, "Numerous classes of prescription medications can interact with alcohol, including antibiotics, antidepressants, antihistamines, barbiturates, benzodiazepines, muscle relaxants, non-narcotic pain medications and anti-inflammatory agents, opioids, and warfarin. In addition, many over-the-counter and herbal medications can cause negative effects when taken with alcohol." Others include analgesics, aspirin, insulin, and oral contraceptives. "The list of medications that may interact with alcohol is so long that you should always consult a pharmacist or physician before drinking while using any medicine."
Older people because their bodies may be less able to handle the effects of alcohol. Older people are urged "to consider drinking less than the levels set in Guideline 1" (i.e. no more than 2 standard drinks a day).
Young adults (aged about 18–25 years) are urged to drink no more than 2 standard drinks a day.
Young people (up to about 18 years) "should not drink to become intoxicated."
People who are or have been dependent on other drugs
People who have a poor diet, or are under-nourished
People who have a family history of cancer or other risk factors for cancer (see Alcohol and cancer for details of how alcohol affects the risk of various cancers)
People who are told not to drink for legal, medical or other reasons
"People who choose not to drink alcohol should not be urged to drink to gain any potential health benefit, and should be supported in their decision not to drink. … Non-drinkers can use other strategies, such as regular exercise, giving up smoking, and a healthy diet, to gain protection against heart disease."
The standard guidelines may be too high when:
undertaking activities that involve risk or a degree of skill such as flying, scuba diving, water sports, ski-ing, using complex or heavy machinery or farm machinery, and driving.
suffering an acute or chronic physical disease such as heart and lung disease, influenza, diabetes, epilepsy or acute infections
recovering from an accident, injury or operation
taking sleeping pills or tranquillisers, anti-depressants or narcotics
responsible for the safety of others at work or at home
United Kingdom: 3–4/day; Advice on weekly consumption is avoided
Therefore, these countries recommend limits for men in the range 20–40 g per day.
Daily/weekly maximum drinks
These countries recommend a weekly limit, but intake on a particular day may be higher than one-seventh of the weekly amount.
Canada: 2/day; 14/week (@13.6 g = 27.2 g/day, 190 g/week)
Hong Kong: 3–4/day; 21/week (glass of wine or a pint of beer)
New Zealand: To reduce long-term health risks, 3/day (30 g/day); 15/week (150 g/week); At least two alcohol-free days every week To reduce risk of injury per occasion: 5 standard drinks (50 g) on any single occasion.
USA: 1–2 units/day (14–28 g/day), not to exceed 14 units/week (196 g/week)
Therefore, these countries recommend limits for men in the range 27.2–32 g per day and 168–210 g per week.
United Kingdom: 2–3/day. Advice on weekly consumption is avoided
Therefore, these countries recommend limits for women in the range 16–30 g per day.
Daily/weekly maximum drinks
These countries recommend a weekly limit, but your intake on a particular day may be higher than one-seventh of the weekly amount.
Canada: 2/day; 9/week (@13.6 g = 27.2 g/day, 122.4 g/week)
Hong Kong: 2–3/day; 14/week (glass of wine or a pint of beer)
New Zealand: To reduce long-term health risks - 2/day (20 g/day); 10/week (100 g/week); At least two alcohol-free days per week To reduce risk of injury per occasion, 4 standard drinks (40 g) on any single occasion
Excessive drinking in pregnancy is the cause of Fetal alcohol syndrome (BE: foetal alcohol syndrome), especially in the first eight to twelve weeks of pregnancy. Therefore, pregnant women receive special advice. It is not known whether there is a safe minimum amount of alcohol consumption, although low levels of drinking are not known to be harmful. As there may be some weeks between conception and confirmation of pregnancy, most countries recommend that women trying to become pregnant should follow the guidelines for pregnant women.
Australia: Total abstinence during pregnancy and if planning a pregnancy (New guidelines were adopted on 6 March 2009).
Canada: "Don't drink if you are pregnant or planning to become pregnant."
New Zealand: "Women who are pregnant or planning to become pregnant should avoid drinking alcohol. The message from health practitioners to abstain from alcohol during the entire pregnancy is unequivocal and should be promoted by all health practitioners."
UK: Avoid alcohol for first 3 months of pregnancy. NICE guidelines issued in March 2007 state, "If you are pregnant or planning to become pregnant, you should try to avoid alcohol completely in the first 3 months of pregnancy because there may be an increased risk of miscarriage. If you choose to drink while you are pregnant, you should drink no more than 1 or 2 UK units of alcohol once or twice a week. There is uncertainty about how much alcohol is safe to drink in pregnancy, but at this low level there is no evidence of any harm to the unborn baby. You should not get drunk or binge drink (drinking more than 7.5 UK units of alcohol on a single occasion) while you are pregnant because this can harm your unborn baby."
US: Total abstinence during pregnancy and while planning to become pregnant
In short, all countries listed above, with the exception of the UK, recommend that pregnant women abstain from alcohol consumption.
"Alcohol passes to the baby in small amounts in breast milk. The milk will smell different to the baby and may affect their feeding, sleeping or digestion. The best advice is to avoid drinking shortly before a baby’s feed." "Alcohol inhibits a mother’s let-down (the release of milk to the nipple). Studies have shown that babies take around 20% less milk if there’s alcohol present, so they’ll need to feed more often – although infants have been known to go on ‘nursing strike’, probably because of the altered taste of the milk." "There is little research evidence available about the effect that [alcohol in breast milk] has on the baby, although practitioners report that, even at relatively low levels of drinking, it may reduce the amount of milk available and cause irritability, poor feeding and sleep disturbance in the infant. Given these concerns, a prudent approach is advised."
Australia: Total abstinence (New guidelines were adopted on 6 March 2009.)
Iceland: Advise that women abstain from alcohol during breast feeding because no safe consumption level exists.
New Zealand: "Alcohol should be avoided during breastfeeding, particularly in the first month, when it is important for sound breastfeeding patterns to be established..."
United Kingdom: "The occasional drink — one to two units [8–16g] no more than once or twice a week — probably won't do any harm. Any more than this isn't good, as it can make the baby so sleepy that it won't take enough milk."
Countries have different recommendations concerning the administration of alcohol to minors by adults.
United Kingdom: Children aged under 15 should never be given alcohol, even in small quantities. Children aged 15–17 should not be given alcohol on more than one day a week — and then only under supervision from carers or parents.
^Sheldrake, Sean; Pollock, Neal W. "Alcohol and Diving". In: Steller D, Lobel L, eds. Diving for Science 2012. Proceedings of the American Academy of Underwater Sciences 31st Symposium. Dauphin Island, AL: AAUS; 2012. Retrieved 2013-03-06.