When it was written (in 1726?) it wasn't written as a childrens book, but as satire of various political situations as well as the many "Travellers Tales" that were common at the time. Still a good read
Yes, be careful. "Gullivers Travels" by Jonathan Swift is available in various adbridged versions that make the story more suitable for children, including versions that take out whole sections of the story. Best make sure you go for an unabridged edition.