The association's telephone lines were said to have been "red hot" this week with calls from members who are caught between concern for pupils, unwillingness to act as paramedics and pressure from their professional body. An AHTS bulletin declares that the association "will not support a member who personally routinely administers medicine to children".
Local authorities have generally given discretion to headteachers. A Strathclyde spokeswoman said that if legal action was taken against a headteacher the council as employer would be liable for any injury caused to a pupil as a result of mistakes by staff.
Frank Mitchell, the AHTS official who wrote the bulletin, replied: "It will not be the director of education who will appear before the court and be exposed in the press in such situations. It will be the individual headteacher."
Mr Mitchell, head of Crawforddyke primary in Carluke, stressed the association's advice had legal endorsement.
Authorities have attempted to deal with the situation by calling for volunteers to administer medicines in schools where children are known to be at risk. Training would be provided.
The latest move came on Tuesday from Grampian's education committee which approved a report on the handling of children with peanut and other serious food allergies who can suffer anaphylactic shock. The report, which had full backing from the teaching unions as well as health professionals on a regional working group, said the authority would "assure the indemnity of trained, volunteer teaching staff who give medical treatment".
Bruce Robertson, Grampian's assistant director of education, said he was "extremely concerned" by the AHTS's advice. Mr Robertson urged heads who were in any doubt to contact the education authority for advice and support.
Other councils such as Tayside have proposed that special contracts should be drawn up involving schools, parents and family doctors. The AHTS has told its members to reject such a proposal.