Lemon tek, shroom tea with as much fungal material removed as possible, or if you have the stomach for it chewing really well and chewing on fresh ginger afterwards.

All three ways have dramatically helped my imaginary friend with their nausea.

Edit: Same imaginary friend had the following to say about acid - if you’re taking a full on, deep diving dose, take the day off and do it in the morning. You’ll probably be good to sleep at a decent time v. doing it in the afternoon/evening. Good trips often require some planning - that’s why they’re called trips!