Avon and Somerset Constabulary is investigating incidents of suspected spiking at Popworld in Weston.
Three separate incidents are believed to have taken place at the Richmond Street venue.
The young women contacted police after noticing puncture wounds on their skin.
Two incidents are thought to have happened during the late hours of December 11 and early hours of December 12, between 8.30pm and 4am.
One incident is also believed to have taken place the weekend prior, December 4-5 between 9pm and 1am.
Georgia Vigo-Hartley, age 20, is one of the young women who was spiked in the line to Popworld on Saturday night. She was enjoying drinks with her friends and family before 'blacking-out'.
Georgia told the Mercury: "I was in the line to Popworld for about 25 minutes when we decided to go to Loft.
"I told my partner that I thought I was spiked because I felt really slow - very different to being drunk.
"After that I blacked-out until about 7am and can't remember anything during the night.
"Because I know I never left my drink unattended, in the morning I looked and found a needle mark under my arm where my dress was open."
A spokesperson for Popworld, said: "The safety and wellbeing of our guests is an utmost priority.
"Our safety measures include searches on entry, publicising 'Ask Angela' in our toilets and providing drinks covers to anyone who wants them.
"Popworld will assist police with any investigation and have CCTV available for inspection.
"We would really like to speak directly to anybody who has a specific concern.
"We continue to work with the police and local authorities to ensure a safe night out is had by all."
Police are 'keeping an open mind' as to whether the three incidents are linked whilst enquiries are ongoing.
A spokesperson for Avon and Somerset police said: "Officers are keen to hear from anyone who has information which could help, especially anyone who was at Popworld on either of the two nights and noticed anything suspicious.
"Please call 101 with any information, phone footage or photos from the club on those nights and give the reference 5221285776 (December 4-5) or 5221291476 (December 11-12)."
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