The Shampoodle is a fictional creature described as a giant, furry, and friendly beast who lives in Giant Country. The BFG, a friendly giant, uses the Shampoodle's fur to make his special "dream-catching" net.
It's not a toy or a shampoo, and there is no connection to toxicity for children. It's simply a part of the fantastical world Dahl created in his book.
If you're curious about the book or the character, I recommend reading it! It's a fun and imaginative story for all ages.