Half of children (50%) think they have seen their parents drunk at some time, according to a survey published.
Almost a third (30%) of children feel scared when they see adults drinking, the study for CBBC's Newsround discovered.
Nearly three-quarters of the children questioned (72%) said their parents drink alcohol.
Of those, seven out of 10 (70%) thought they had seen them drunk.
Just less than half of the children (46%) surveyed thought that adults should not drink in front of children, while 32% thought this was all right, and 22% were not sure.
When given a list of words to describe how they felt when they saw adults drinking, almost half the children (47%) said they were not bothered. But 30% said it made them feel scared.
Eight in 10 children (81%) surveyed who had seen adults drinking said they noticed one or more changes in the way they behaved.
Of those, almost a quarter (24%) said it made adults act stupid or silly; a fifth (20%) said they became angry and aggressive; another fifth (20%) said they became happy and funny; 19% found them to act strangely or in a different way; 18% said they became loud and swore; and 17% said they became dizzy or fell over.
The results will be revealed on CBBC's Newsround on BBC1 at 4.55pm as part of a wider exploration of the issue of alcohol and how adults' drinking affects children's lives.
Damian Kavanagh, Controller of CBBC, said: "Newsround has a great track record in covering complex issues in an engaging and helpful way. There has been much discussion about levels of drinking but the social impact is rarely explored from a child's point of view."