Alicia Silverstone refuses to give her son medicine.

The 37-year-old vegan star told PEOPLE.com that her son "has never been sick."

She added: "I'm not against Western medicine. The problem is we're using it as a first step for everything, even when it's not needed."

Alicia also wrote in her new book, 'The Kind Mama': "There is increasing anecdotal evidence from doctors who have gotten distressed phones calls from parents claiming their child was 'never the same' after receiving a vaccine. And I personally have friends whose babies were drastically affected in this way."

Encouraging other parents to "get educated and make a decision that feels best for you," she added: "Vaccines are a very complicated issue."

Alicia also said Bear has rarely been sick as a result of his healthy diet.

She said: "Because his body is a super-clean, healthy machine it can defend itself and flush out all the nasty stuff much more quickly than a baby whose diet isn't as kind."

The blonde beauty has previously attracted criticism for some of her parenting skills, including chewing her son's food before giving it to him, and ingesting her placenta through a pill.

But earlier this week, she said: "As far as critics, I'm very secure in the choices I make because I'm really informed and I trust my instincts and when I need help, I go to the people I see parent or birth or be pregnant in a way that was really inspiring me. And the rest is just noise."