Pharmacists have faced abuse from customers trying to get medicines as the coronavirus crisis continues.
Chemists are among the businesses allowed to remain open in the UK.
Elen Jones, of the Royal Pharmaceutical Society in Wales, told BBC Radio Wales such behaviour was not acceptable.
She said pharmacies were getting between three times normal daily prescriptions and up to a week's worth a day.
Pharmacists were working 12-hour plus days.
"We are concerned that we have received a number of reports from our members about abusive and aggressive behaviour towards them and their teams," Ms Jones said.
"It is absolutely not acceptable behaviour at any time, but particularly when teams are working tirelessly, and under such stress to cope with increasing demand."
Assistant director of pharmacy for Betsi Cadwaladr health board's central area, Bill Duffield, said colleagues were under "immense pressure."
"They're having to deal with multiple questions from people coming up to the counter and not observing the two-metre barriers, as well as the supply issues," he said.
They had been coping been with "several months" of work in just a few weeks.
"People need to be respectful of social distancing because pharmacy staff are in the front line." Mr Duffield said.
"We're preparing for critical care areas," said Lois Lloyd, who runs medicine procurement and home care for the health board across north Wales.
"We have got plans in place and are building up the contingency.
"We're not stockpiling but we do have supplies coming in and we will have stock when we need it."
Some pharmacists have taken measures including wearing masks and gloves and separating customers from staff with perspex screens.
Health minister Vaughan Gething urged pharmacies not to charge for prescription home deliveries.
Porthcawl Butchers said they were stopping home deliveries because of an "intolerable level" of abuse from some customers.