Abstract The slime toys were invented by Mattel in 1976. Slime is a reversible cross-linking gel made from guar gum. The slime toys were further developed into many different products and became one of the most popular toys. Despite buying slime products with attractive packaging, some children love to make their own slime products. The Consumer Council of Hong Kong published a report in 2019 to alert the public about the safety problems because of the excess boron content in those slime products in 2019. Some reported cases of slime product players having adverse health symptoms, which made the government concerned about the safety of slime products. The objectives of the study were to investigate the concentration of boron compounds in the four selected slime toys from the market and suggest a safety ingredient formula to the users to make their own do-it-yourself slime toys. Because only the European Union has relevant safety regulations and standards to limit the concentration of boron compounds in the toys, amendment of the current children’s products safety regulations and standards is required. By fulfilling the objectives, the consumers can make sure that their children who play with slime products can do so without the potential adverse health effects.