Go through these in order and stop at the first one that applies. If you are reading this for someone else, answer for them.
Contact your local poison centre or emergency medical service immediately.
In the United States, Poison Help is available at 1-800-222-1222 .
Call emergency services now if the person has:
And for anyone, someone who:
Treat any suspected swallowing of jimsonweed as urgent, even if symptoms have not started.
After discharge, seek urgent reassessment if confusion returns, urine becomes very dark, urination stops, severe muscle pain develops, vomiting prevents drinking, or breathing becomes difficult.
Routine follow-up is appropriate for lingering mild blurred vision, fatigue, concentration problems, or questions about an intentional exposure, provided symptoms are improving and no urgent warning signs are present.
The article also says
Do not let a confused person drive themselves to care.
Keep them away from traffic, stairs, water, heat, and objects that could cause injury.
Do not put anything in the mouth of someone having a seizure.
Every sign above is quoted from the sofidex article on Jimsonweed poisoning. If you are not sure, err upward — it is always reasonable to be checked.