I have heard that Borax powder is toxic for dogs!
Toxicology
Based on mammalian
median lethal dose (LD50) rating of 2,660 mg/kg body mass, boric acid is poisonous if taken internally or inhaled in large quantities. However, it is generally considered to be not much more toxic than
table salt.
[4] The Thirteenth Edition of the
Merck Index indicates that the LD50 of boric acid is 5.14 g/kg for oral dosages given to rats, and that 5 to 20 g/kg has produced death in adult humans. The LD50 of sodium chloride is reported to be 3.75 g/kg in rats according to the
Merck Index.
Long term exposure to boric acid may be of more concern, causing kidney damage and eventually kidney failure (see links below). Although it does not appear to be
carcinogenic, studies in dogs have reported
testicular atrophy after exposure to 32 mg/kg bw/day for 90 days. This level is far lower than the LD50.
[5]
According to boric acid IUCLID Dataset published by the European Commission, boric acid in high doses shows significant developmental toxicity and
teratogenicity in rabbit, rat, and mouse fetuses as well as cardiovascular defects, skeletal variations, mild kidney lesions.
[6] As a consequence, in August 2008, in the 30th ATP to EU directive 67/548/EEC, the EC decided to amend its classification as reprotoxic category 2 and to apply the
risk phrases R60 (may impair fertility) and R61 (may cause harm to the unborn child).
[7][8][9][10][11]