Paul Coppeard, from Hope UK, told Premier's News Hour parents need to be better-informed.
He said: "It's appalling, there's so much education that needs to go on with parents.
"We know our youngsters are getting education about the issues around alcohol and drugs, but our parents just don't seem to have it, and I don't know where they're getting the idea of using it as bribes from - something that's actually a poison to your system - it doesn't seem like a good idea at all really."
He was speaking after new research shows that parents are ignoring medical advice by letting their youngsters try alcohol.
- 1000 parents asked
- 50% say children under 14 allowed to drink alcohol at home
- 11% say children aged five to seven allowed to try alcohol at home
Churchill Home Insurance surveyed more than 1,000 parents and found that 34% of them with children under 14 used alcohol as a bribe to encourage good behaviour.
11% of parents with children aged five to seven allowed them to try a drink at home and a quarter of those surveyed who let their children drink said they saw nothing wrong with it.
It is not illegal for children aged five to 16 to have alcohol at home.
However, the Chief Medical Officer's report states that children under 14 who drink have increased health risks - including suicide attempts, involvement in violence and alcohol-related injuries.
Paul Coppeard said: "It's so difficult, because you can't just give a hard and fast rule.
"Parents do need to teach about alcohol to their children, they also need to show their children they can enjoy themselves without the use of alcohol."
He went on: "The fact still remains that the longer a young person steers clear of alcohol, the better it is for them, not only for their health, but also with possible bad outcomes with alcohol later on in life."
Almost a third of parents said that allowing their children to drink at home let them monitor their child's alcohol consumption.
The research also suggested that one in five parents would allow minors who are not family members to have alcohol in their house.
Listen to Premier's Aaron James speak to Paul Coppeard here:
