Ms Tsui declined the offer and took the woman's contact details at her request before escorting her from the church.

The box was picked up by a staff member who found it on the church porch. It was later shared by six people after a church meeting on the same day, the cleaner said.

One girl and two boys, aged between 12 and 15, felt unwell an hour after each ate a piece of pastry, which they said had a bitter taste, the court was told.

They were admitted to hospital the same night and remained there up to a week for an overdose of Risperidone, a prescription drug commonly used in treating schizophrenia. Overdose symptoms include nausea, a fast heart rate, difficulty breathing, and restless muscle movements in the eyes, tongue or neck.

Chan pleaded not guilty to three counts of administering poison or another destructive or noxious substance with intent to injure, aggrieve or annoy.

Ms Tsui, who had worked at the church for more than 31 years, said she did not know the defendant.

The cleaner joined a police patrol on August 21 in the area of the address Chan had left. When they found the woman at a bus terminal, she denied meeting Ms Tsui. Prosecutor Peter Lo Man-chiu said Chan did not live at the address she had left.

Police later located her home and seized six anti-psychotic pills prescribed to the defendant, three of which were Risperidone.

There was also a note that bore the same contact details she had left with the church, the prosecutor said.

A chemist's report said Risperidone was found in three of five leftover pastries and the box.

The trial continues today before District Court judge Joseph Yau Chi-lap.