Acronym for "Switch Back To Homegrown" as used in chats and, occasionally, email exchange.

The meaning can be derogative, funny or both, depending on context.

"Homegrown" refers to home grown marijuana plants that are (supposedly) free of side effects, when consumed as a drug, as they are grown under known conditions.

Marijuana obtained from a third party (non home grown) may have been mixed with unknown substances that can cause its user to experience "side effects".

In this case the user of the acronym indicates aformentioned side effects may have caused the addressee to write nonsense in the chat/email exchange at hand.
Dude, SBTH. This makes no sense whatsoever.
by virtualritz May 6, 2010
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