What is the best evidence available relative to chamomile having relaxing effects?
Some examples claims include:
There is a website by the NIH about Chamomile listing the evidence for effectiveness for medicinal purposes.
The short summary is, there is insufficient evidence for effectiveness for any of the conditions it is used for. This does not mean that it absolutely does not work, but it means we don't know whether it does anything at all.
In absence of any evidence there are two major side effects listed, one is the possibility of miscarriage when taken during pregnancy, the second one are possible allergies.
I cannot recommend taking pharmacologically active substances with doubtful efficacy.
The chamomille used as herb at least in Central Europe is German chamomile (Matricaria recutita, also known as Matricaria chamomilla).
About its medicinal effects following is said on Wikipedia:
A 2006 review of the medical literature reported a number of beneficial effects for chamomile in in vitro and animal tests, but added that more human clinical trials are needed before firm conclusions can be drawn. Research with animals suggests antispasmodic, anxiolytic, anti-inflammatory and some antimutagenic and cholesterol-lowering effects for chamomile.[9] Chamomile has sped healing time of wounds in animals.[10][11] It also showed some benefit in an animal model of diabetes.[12] In vitro chamomile has demonstrated moderate antimicrobial and antioxidant properties and significant antiplatelet activity, as well as preliminary results against cancer.[7][13]
Another study which might be relevant is Chamomile Capsules Ease Anxiety Symptoms
