The reason we have to put a warning to not use BON in case of hemophilia or the intake of anticoagulants on our boxes and products is that the Bed of Nails has sharp spikes. Even though these spikes are rounded and do not puncture the skin, there is a chance that you may scratch yourself when making sudden and unfocused movements.The anticoagulant medication makes your blood thinner and prevents it from coagulating properly. This means that if you happen to scratch your skin, the blood may not stop bleeding as easily. We recommend speaking to your doctor for further advice on whether they think Bed of Nails is a good option while taking these medications.