A "bad batch" of illicit pills has seen 12 people rushed to an Adelaide hospital, prompting a warning from doctors

The average Saturday night sees one or two drug-related presentations at Royal Adelaide Hospital.

But over a 24-hour period 12 people, who'd they'd taken recreational drugs in tablet form, arrived at the emergency department where they were found to have significant toxicity.

The patients were found collapsed or unconscious before being taken to hospital on Saturday with agitation, nausea or vomiting, and exhibiting behavioural disturbances.

None of the 12 patients died and all have since been discharged, but the spike has doctors concerned about an "increased risk" for drug takers.