This finding was reported in 2005. So, not every study or clinical trial has found this herb to be effective in treating anxiety and insomnia.Nevertheless, German health officials have approved this herb as a mild sedative and sleep aid on the basis of the findings of some animal studies and clinical trials. But many experts are of the opinion that more research is needed to find out the efficacy of this herb in promoting sleep or reducing anxiety. Possible Side Effects » Valerian is generally considered safe. As mentioned already, this herb is not addictive in nature, and it usually does not cause dependency and withdrawal symptoms, though it affects the central nervous system. It has not been found to cause any major side effects. However, some individuals can experience a few minor discomforts like Headaches Dizziness Gastrointestinal problems Apathy Drowsiness In addition to these side effects, people allergic to this herb can develop an allergic reaction after ingesting it, which can produce the following symptoms: ? Skin rash and hives Unusual swelling of the mouth, throat, and the lips Shortness of breath and wheezing » The excessive use of valerian, and the simultaneous use of alcohol and valerian can damage the liver, which can produce symptoms like pain in the upper right portion of the abdomen and jaundice. Jaundice can cause yellowing of the white portion of the eye, as well as the skin. People with preexisting liver diseases should avoid this herb and its supplements, or talk to their physicians before using it.