Preliminary lab tests showed that gummy ring candy from the party contained THC, the psychoactive ingredient in marijuana.
"Anyone who attended the quinceañera and may have taken home some of the gummy rings is urged to discard them immediately," said Dr. Tomas Aragon, health officer for the city and county of San Francisco.
The 19 people were taken to the hospital Saturday with symptoms ranging from a rapid heart rate and dilated pupils to nausea, lethargy and confusion. All were released by Monday morning.
Health officials are investigating the origin of the candy, including the catering company, which is from Oakland, officials said.
"The question remains, where did the candies come from?" said Aragon.
He warned of the dangers of edible marijuana at parties where it can be hard to control the dosage.
"A situation like this, where they were consumed by unsuspecting people, and many children, is greatly concerning," Aragon said.
A quinceañera is a celebration of a girl's 15th birthday in some Latin American cultures.
24 sent to hospital in Ohio
THC in candies also sent 24 music festival attendees to the hospital in Richland County, Ohio, on Saturday, according to the county sheriff's office. No one lost consciousness and everyone seems to be OK, Sheriff's Capt. Donald Zehner said.
A 28-years-old man from Michigan was arrested in connection with the overdoses, the sheriff's office said Monday.
Paramedics initially believed the overdoses were caused by opiates, but when victims did not respond to the antidote Narcan, the candies were tested and came back positive for a high dosage of THC, CNN affiliate WEWS
The overdose victims Saturday were attending the EST FEST music festival in Butler, Zehner said.
Synthetic cannabinoids can be anywhere from two to 100 times more potent than natural THC, according to the Centers for Disease Control and Prevention.
They are generally unpredictable because of the unknown chemical composition of the drugs, which, the National Institute on Drug Abuse noted, may change from batch to batch.