What does it mean dilating blood vessels 
Really good explanation from wikipedia.
"Vasodilation refers to the widening of blood vessel resulting from relaxation of smooth muscle cells within the vessel walls, particularly in the large veins, large arteries, and smaller arterioles. The process is essentially the opposite of vasoconstriction, which is the narrowing of blood vessels.
When blood vessels dilate, the flow of blood is increased due to a decrease in vascular resistance. Therefore, dilation of arterial blood vessels (mainly the arterioles) causes a decrease in blood pressure. The response may be intrinsic (due to local processes in the surrounding tissue) or extrinsic (due to hormones or the nervous system). Additionally, the response may be localized to a specific organ (depending on the metabolic needs of a particular tissue, as during strenuous exercise), or it may be systemic (seen throughout the entire systemic circulation)."
To summarise, relax the blood vessels and blood pressure decreases. This is why ginkgo is sometimes used in chinese medicine (and just by normal Asian doctors) to treat hypertension. Vinpocetine is another substance that has a similar effect. Oddly enough, I had a grandfather who used to consume a lot of seaweed and periwinkles as he said they gave him energy and kept his mind sharp. This was probably the benefits of tyrosine and vinpocetine. Perhaps he had some form of POIS but never knew it.
There are so many ginkgo brands available online. The first brand I got was Vogel which is expensive but seemed of a very high quality but there are so many others. I like companies like Now Foods simply because they have their own laboratories and as I said in a previous post I am very wary of supplement companies that are merely marketing companies where all the products are created and tested elsewhere. My only guide on picking a manufacturer for these things would be
1) is the company in business long? (check their website)
2) have they had product quality issues in the past (check the internet)
3) do they have offices in your country or a nearby country. If so, then that's useful as if something goes wrong they're bound by the laws of your country and will have to take more care in dealing with any customer complaints.
