Zahlavova Strycova, ranked 124 in the world, tested positive for the stimulant sibutramine last October, the International Tennis Federation said in a statement.
The 26-year-old denied any intent to enhance her performance and said the stimulant had got into her system through her use of a dietary supplement.
"She is suspended from participation for a period of six months, back-dated to commence from 16 October 2012 and so ending at midnight on 15 April 2013," the ITF said in a statement.
"The ITF did not dispute Ms Zahlavova Strycova's account of the circumstances surrounding her ingestion of sibutramine."
Zahlavova Strycova's results from the Luxembourg Open and the ITF Bueschl Open will be disqualified and she will forfeit the ranking points and prize money she won at those events.