Because of the anesthesia your docs will give you before surgery. Should also not be taken with alcohol. It is safe to take. Good stuff!!

10 types of cancer?? Give me a break, or at least cite your sources for all these extreme contraindications. If you get it from a poor source, then yes, like everything else, you might get what you pay for. If you get valerian from a reputable, organic source, there are not that many serious contraindications.

“The American Herbal Products Association (AHPA) gives valerian a class 1 safety rating, which indicates that it is a safe herb with a wide dosage range. ” – University of Maryland Medical Center

Yes, it is a sedative, and therefore by common sense it should be kept away from any other sedative or psychiatric meds or herbs. So no anti-depressants, anti-convulsants, or sedatives of any kind while on valerian. Some psych meds might stay in your system for a long time, so ask a pharmacist if you were on any drugs like that in the past few months.

The one side effect I have found in speaking with other herbalists, is that nightmares result for some people. Out of the 25 or more people I know on valerian, three of the reported this. There are likely studies out there which can reflect a more accurate idea of how many people get this.

According to the American Botanical Council cited below, most people don’t have any problems at all with it. They are even recommending it as safe during pregnancy, although I would look into this more before suggesting it.

The other reference I cited below is the University of Maryland Medical Center, and it has more info about some other possible side effects.

As far as i know Valerian is one of the safest natural alternatives to sleep aid and anti-stress drugs.

Valerian root is a natural relaxant, and will definitely cause you to be drowsy.
as far as discontinuing before surgery, it is because it may amplify any other drugs you are given. stopping all herbal supplements and extra vitamin e is also advisable, as they may cause un wanted amplification of your prescribed drugs.

Several people recommended Valerian to me as an alternative to anti-seizure drugs that I was experiencing side effects from. When I questioned my doctor about this he informed me that Valerian has pretty much the same side effects as Valium so be careful. here are some warnings I found.
Do not use valerian in a bath without first talking to your doctor if you have a skin injury, a skin illness, a fever, an infection, or heart problems. This could be dangerous and should occur only under the supervision of a doctor.
Use caution when driving, operating machinery, or performing other hazardous activities. Valerian may cause drowsiness and dizziness. If you experience drowsiness or dizziness, avoid these activities.

Before taking valerian, talk your doctor if you are taking muscle relaxants, other sleep or anxiety medicines, pain medicines, antidepressants, or other medicines that cause drowsiness. These drugs may increase drowsiness and dizziness while you are taking valerian.

Use alcohol cautiously while taking valerian. Alcohol may increase drowsiness when used with valerian.

Valerian has not been evaluated by the FDA for safety, effectiveness, or purity. All potential risks and/or advantages of valerian may not be known. Additionally, there are no regulated manufacturing standards in place for these compounds. There have been instances where herbal/health supplements have been sold which were contaminated with toxic metals or other drugs. Herbal/health supplements should be purchased from a reliable source to minimize the risk of contamination.