Three children were taken to hospital after their grandmother gave them cakes from a cancer charity stall without knowing they were spiked with cannabis.
The children, aged five, four and 14 months, felt giddy and spent six hours under observation in a Swansea hospital. Two people were arrested.
Their grandmother, who has not been named, bought half-a-dozen cakes at a charity event at a Port Talbot hotel.
Police said the charity knew nothing about where the cannabis came from.
The grandmother gave the cakes to her daughter after taking them home from an event at the Dunes hotel in the Sandfields area, which was selling a wide-range of food to raise money for charity.
Det Insp Wayne Thomas, of South Wales Police, said: "Some time later her daughter and three grandchildren ate the cake and started to feel queasy.
"The children's mother rang the hotel and said 'what was in those cakes? We're all feeling funny'.
Accident and emergency
"She was told that the cakes may have contained a special ingredient and only meant to be sold to people who were specifically aware what was in them.
"It was then the family realised they may have been laced with cannabis."
The children were detained at the accident and emergency department of Singleton Hospital.
"Fortunately, they were not in any danger and there will be no lasting effects," said Det Insp Thomas.
Two people arrested on suspicion of the possession and supply of drugs were released on police bail for three weeks.
Det Insp Thomas said: "We are anticipating further arrests and our investigations are continuing."
"I would emphasise that the charity had no knowledge of the incident and was not involved in any way."
http://news.bbc.co.uk/1/hi/wales/4246418.stm