There are many conventional medications that are both safe and effective, and used properly the pose no danger, herbal remedies and essential oils are the most effective and side effect free way of treating certain conditions, from pain to gout and even cancer, (I never recommend using these without consulting a doctor) these substances never have side effects and the are effective a targeting specific conditions when properly understood and administered, however the 4th cause of poisoning in the U.S. is with herbal medications, this is because many underestimate their potency and over use them, if you do choose to use them please educate yourself and most importantly if your currently taking conventional medications CONSULT YOUR DOCTOR FIRST as some interactions can be deadly.
While I appreciate the sentiments expressed in this post there are some inaccuracies here.
If any substance has a pharmacologic effect i.e. potentially actually works on the body in some way then it is also potentially dangerous.
Jonah is correct in saying that a large percentage of accidental poisonings involve herbal remedies.
However there is no completely safe, and side effect free, agent that actually works.
If a claim of 100% safety is true then that agent is a placebo - in other words it has no effect.
One of the biggest myths that circulate around herbal remedies is that they cannot harm you - that is complete nonsense.
Many people also have similar views about more conventional medications that are available "over-the-counter".
Paracetamol, for example, causes more medication-related deaths than any other medication known.
(I am not referring to deliberate overdose here either.)
Of course, the reason is partly due to the fact that it is also the most commonly taken medication on the planet.
Paracetamol can be very safe when it is appropriately selected, but it can be deadly when taken in the wrong situations.
The key point here is that no agent, howsoever marketed, that actually works (has a pharmaceutical effect) can be said to be unequivocally and unconditionally safe.
Jonah is absolutely correct in advising that individuals consult with their doctors before taking ANY pharmaceutical agent, whether marketed as herbal or traditional, or not.
This is even more important if one is already taking medication for other purposes.
Disclaimer: I am a physician. I have no pecuniary interest in any pharmaceutical or herbal remedy company. I will not answer any questions related to specific agents. The content above should be interpreted as general advice only.