An ostomy barrier seal comprising an open-ended conical base 1; and a flange portion 2 extending radially from the base; wherein the conical base 1 has a top opening 3 and a bottom opening 5 for receiving a stoma of a user and the top opening diameter 9 is smaller than the bottom opening diameter 11; such that the stoma of the user fits through the bottom opening and the top opening expands to snuggly fit around and seal along the stoma wall; a related ostomy appliance incorporating the barrier seal; and a related method using the barrier seal to reduce the incidence of waste leakage in an ostomy patients.