Here is a site that says that it is a "regenerated cellulose fiber".
That sounds to me as though the yarn is not spun from bamboo fibers,
as linen is, but "regenerated", which sounds rather like ... well,
Here is another description:
And this: note that the bamboo used is "of good character and ideal temper".
Can't get any friendlier than that - plus being antibacterial:
Only the cached site for this could be opened, but here is the whole text:
www.pcarrd.dost.gov.ph/cin/bamboonet/technology%20-%20clothes.htm - 18k -
"Clothes Made From Bamboo Fibers
In Yunan, China, 100% bamboo fiber is being processed into a bamboo
fabric. Three to four years old green bamboo are used to produce
natural and eco-friendly fiber without any chemical additives.
The bamboo fiber fabric production flow is: bamboo -> thick pulp ->
fine pulp -> bamboo fiber -> bamboo yarn -> fabric.
Bamboo pulp is refined from bamboo through a proocess of
hydrolysis-alkalization and multi-phase bleaching. Afterwhich, bamboo
pulp is processed into bamboo fiber. Repeated tests have proven that
bamboo fiber has strong durability, stability, and tenacity. The
thinness and whiteness of bamboo fiber is similar to classic viscose.
Moreover, because of the bamboo fiber's abrasion-proof capacity, it
spins nicely from bamboo fibers are now being exported to Europe.
Source: China Bamboo Textile Co., Ltd; http://www.bambrotex.com"
I have the impression that they are all being coy, as here, when they
say "bamboo pulp is processed into bamboo fiber".
Normally with spun natural fibers, producers brag about their length:
"long staple cotton".
But I may be wrong; wouldn't be the first time.