Chewing gum is a soft, cohesive substance for chewing but not swallowing. Humans have used chewing gum for at least 3,000 years. Chewing gum was originally made of chicle, a natural latex. By the 1960s, chicle was replaced by butadiene-based synthetic rubber which is cheaper to manufacture. Most chewing gums are considered polymers.Chewing gum in many forms has existed since the Neolithic period.