Be in a calm, safe environment and have gentle reassurance that everything will be OK, is the primary treatment.
A large 50-200mg dose of CBD (without significant amounts of THC) can mitigate the effects of THC thus can act as a partial antidote. Lemon oil, found predominantly in the rind and lower amounts in the juice, has also been used historically for this purpose. Grate a tablespoon of lemon zest and chew it up before swallowing.
Most people do not need emergency medical care unless they have pre-existing heart disease or another serious medical condition. For ongoing vomiting and diarrhea, intravenous rehydration may be necessary. Start Low and Go Slow!!!
We hope this helps you to feel more confident and comfortable consuming, gifting & sharing with anyone.