Information about hyoscyamine (the main active alkaloid in Datura stramonium seeds) taken from
Hyoscyamine Uses, Side Effects & Warnings
What is hyoscyamine?
Hyoscyamine produces many effects in the body, including relief from muscle spasms.
Hyoscyamine also reduces the fluid secretions of many organs and glands in the body, such as the stomach, pancreas, lungs, saliva glands, sweat glands, and nasal passages.
Hyoscyamine is used to treat many different stomach and intestinal disorders, including peptic ulcer and irritable bowel syndrome. It is also used to control muscle spasms in the bladder, kidneys, or digestive tract, and to reduce stomach acid. Hyoscyamine is sometimes used to reduce tremors and rigid muscles in people with symptoms of Parkinson's disease.
Hyoscyamine is also used as a drying agent to control excessive salivation, runny nose, or excessive sweating.
Hyoscyamine may also be used for other purposes not listed in this medication guide.
Hyoscyamine Dosing Information
Usual Adult Dose for Irritable Bowel Syndrome:
Immediate-release Tablets: 0.125 to 0.25 mg orally or sublingually every 4 hours or as needed. Do not take more than 12 tablets in 24 hours.
Usual Pediatric Dose for Urinary Incontinence:
Greater than or equal to 2 to less than 12 years:
Immediate-release Tablets: 0.0625 to 0.125 mg sublingually, orally, chew, every 4 hours or as needed. Do not take more than 6 tablets in 24 hours.
How do those doses related to Datura stramonium seeds?
0.0560 mg =
1 average 8 mg seed of maximum 0.7% alkaloid content
0.0625 mg = the minimum dose used for children ages 2-12 for treating urinary incontinence
0.1120 mg =
2 average 8 mg seeds of maximum 0.7% alkaloid content
0.1250 mg = the maximum dose used for children ages 2-12 for treating urinary incontinence
0.1250 mg = the minimum dose used for adults for treating irritable bowel syndrome
0.2240 mg =
4 average 8 mg seeds of maximum 0.7% alkaloid content
0.2500 mg = the maximum dose used for adults for treating irritable bowel syndrome
1.4560 mg =
26 average 8 mg seeds of maximum 0.7% alkaloid content
1.5000 mg = maximum safe dose of hyoscyamine for an adult
0.0240 mg =
1 average 8 mg seed of average 0.3% alkaloid content
0.0480 mg =
2 average 8 mg seeds of average 0.3% alkaloid content
0.0625 mg = the minimum dose used for children ages 2-12 for treating urinary incontinence
0.1200 mg =
5 average 8 mg seeds of average 0.3% alkaloid content
0.1250 mg = the maximum dose used for children ages 2-12 for treating urinary incontinence
0.1250 mg = the minimum dose used for adults for treating irritable bowel syndrome
0.2400 mg =
9 average 8 mg seeds of average 0.3% alkaloid content
0.2500 mg = the maximum dose used for adults for treating irritable bowel syndrome
1.4880 mg =
62 average 8 mg seeds of average 0.3% alkaloid content
1.5000 mg = maximum safe dose of hyoscyamine for an adult
For these medical uses, up to 2 seeds would be used for children ages 2-12, and up to 4 seeds for adults. That's assuming your seeds are super potent 0.7% alkaloid content seeds. Most are about 0.3%, not 0.7%. Some are even 0.1% or less.
The point I'm trying to make here is that Datura stramonium seeds can be used safely if you know what you're doing. Normally 1-4 seeds are all an adult needs for the valuable medicinal effect of hyoscyamine. Any more than that and you're really overdoing it. The only time you might take 26 seeds is if your seeds are fairly weak. 26 maximum potency 8 mg seeds would contain about 1.456 mg of hyoscyamine. The safe limit for an adult is 1.5 mg. Absolutely Never go beyond 26 seeds. 20 is a safer number. For extra safety I would limit it at 10, which is also the limit given in a lot of herb books.
I want to make it clear that hallucinations from Datura are a sign of OVERDOSE. Please do not take enough Datura to experience hallucinations. The overdose needed for that is extremely risky, could put you in a coma or even kill you. That's no joke. Datura stramonium is safe when 10 seeds or less are used. At that dose, none of the overdose symptoms are even remotely possible. Datura stramonium is a valuable medicinal herb with many uses when doses of 10 seeds or less are used. But when people abuse it and take 50-250 seeds to experience hallucinations they are taking huge, possibly fatal amounts. Don't be tempted to do it. Limit yourself to 10 seeds per day, and don't take it everyday. As long as you follow those rules, it's perfectly safe to use.