Even as a visitor and a citizen of another country, when you are in Brazil you are subject to all Brazilian laws. During your travels in Brazil, you may encounter Federal Military Police, Federal Highway Police, Customs Agents, Tax Revenue Agents, and other law enforcement agents, and in cities, Civil Police and Traffic Police. Always obey any order any police officer or agent gives you and always show them courtesy and respect.
It does not matter that you may witness others disobeying laws or are cajoled into going along with the crowd; as a foreigner, you should always obey all laws. A good rule of thumb is to remember that if some thing or some action is illegal in either the US, Canada, the UK, or Australia, it is more than likely that it is also illegal in Brazil.
ALCOHOL
The official legal drinking age in Brazil is 18. While open containers are not prohibited, Brazil does have extremely strict drunk driving laws that are zero tolerance for all intents and purposes. Even one glass of wine or one beer can put you over the limit and bring heavy fines. Read more about the "Lei Seca" here (World Health Organization), here (Trip Savvy), and here (Observatório Nacional de Segurança Viária, in Portuguese).
DRUGS
Approximately 80% of all foreigners in Brazilian prisons are there on drug related offenses. Beware! Brazilian drug laws are, at best, draconian. A drug violation that might result in punishment of little more than a fine, probation, and/or a period of community service in the US, Canada or the UK could put you behind bars for years in Brazil. And, Brazilian jails and prisons make those in Western Europe and North America look like resorts.
Do not use, buy, or traffic (this includes giving drugs away free of charge). In Brazil, illicit drugs include the usual culprits (marijuana, cocaine, heroin, crack, etc., etc.) but also any controlled substance such as prescription (controlled) drugs or medications. If you have a prescription drug in your possession without a bona fide prescription or a supply of any controlled substance that "appears" too large for a single person, you could be in a world of trouble. Brazilian law does not differentiate between, for example, cocaine, opium or heroin and anabolic steroids or pain killers. If it is illicit, it is illicit.
OTHER CRIMES
Brazil has severe laws against the exploitation of minors. If you're caught with an underage child - even if they're plying their "trade" on the street or elsewhere - you are going to jail. You can also be prosecuted in the US (and in the in the UK and many other countries) for crimes committed against minors abroad.
CONSULAR ASSISTANCE IF DETAINED OR ARRESTED
Besides offering advice, there are only a limited number of things that the embassy or consulate of your country can do to help you if you are arrested, charged, convicted, or incarcerated in Brazil. The US Department of State, for example, cannot: get US citizens out of jail, provide legal advice or represent U.S. citizens in court, serve as official interpreters or translators, or pay legal, medical, or other fees. The US State Department outlines what assistance is available to US Citizens arrested abroad here.
Updated November 2017
It does not matter that you may witness others disobeying laws or are cajoled into going along with the crowd; as a foreigner, you should always obey all laws. A good rule of thumb is to remember that if some thing or some action is illegal in either the US, Canada, the UK, or Australia, it is more than likely that it is also illegal in Brazil.
ALCOHOL
The official legal drinking age in Brazil is 18. While open containers are not prohibited, Brazil does have extremely strict drunk driving laws that are zero tolerance for all intents and purposes. Even one glass of wine or one beer can put you over the limit and bring heavy fines. Read more about the "Lei Seca" here (World Health Organization), here (Trip Savvy), and here (Observatório Nacional de Segurança Viária, in Portuguese).
DRUGS
Approximately 80% of all foreigners in Brazilian prisons are there on drug related offenses. Beware! Brazilian drug laws are, at best, draconian. A drug violation that might result in punishment of little more than a fine, probation, and/or a period of community service in the US, Canada or the UK could put you behind bars for years in Brazil. And, Brazilian jails and prisons make those in Western Europe and North America look like resorts.
Do not use, buy, or traffic (this includes giving drugs away free of charge). In Brazil, illicit drugs include the usual culprits (marijuana, cocaine, heroin, crack, etc., etc.) but also any controlled substance such as prescription (controlled) drugs or medications. If you have a prescription drug in your possession without a bona fide prescription or a supply of any controlled substance that "appears" too large for a single person, you could be in a world of trouble. Brazilian law does not differentiate between, for example, cocaine, opium or heroin and anabolic steroids or pain killers. If it is illicit, it is illicit.
OTHER CRIMES
Brazil has severe laws against the exploitation of minors. If you're caught with an underage child - even if they're plying their "trade" on the street or elsewhere - you are going to jail. You can also be prosecuted in the US (and in the in the UK and many other countries) for crimes committed against minors abroad.
CONSULAR ASSISTANCE IF DETAINED OR ARRESTED
Besides offering advice, there are only a limited number of things that the embassy or consulate of your country can do to help you if you are arrested, charged, convicted, or incarcerated in Brazil. The US Department of State, for example, cannot: get US citizens out of jail, provide legal advice or represent U.S. citizens in court, serve as official interpreters or translators, or pay legal, medical, or other fees. The US State Department outlines what assistance is available to US Citizens arrested abroad here.
Updated November 2017