German translation problem - idiom/phrase?

What is a good translation for something "does more harm than good" in german? DO NOT put it into a translation site. Those blow and are almost never right, and only help with grammatical word choices every so often. Like saying "youre crazy" translates to "you have a bird". Ive looked all over the internet and dont find any direct matches and want to make sure the phrase I use is correct and sounds ok. Only answer this if you are a native speaker and have german as a 1st language. Thanks in advance for the help!