Mixing bleach and vinegar is not recommended as it creates a harmful chemical reaction that releases chlorine gas. Chlorine gas is toxic and can be fatal if inhaled at high enough concentrations. Even small amounts of bleach mixed with vinegar can create this gas. Symptoms of chlorine gas inhalation can vary based on the individual, but can include irritation of the eyes and throat, chest heaviness, and breathing difficulties. It is important to avoid mixing bleach and vinegar when cleaning and to only use them separately.