There is provided a new thermo-gelling composition made with methylcellulose and citric acid. This composition may also have an effective amount of a treating agent, which may be a medicinal agent, cosmetic agent, moisturizer, adjuvant, nutritional agent, other ingredients and combinations thereof. The composition is useful in delivering moisturizers or pharmaceutically active agents to the user in a controlled release manner through the mucosal tissues in a body cavity, or on body surfaces, or as a subcutaneously injected medicament. The composition may also be used as a replacement for the soft tissues of the body as in, for example, the foot cushion and cartilage repair.