Tacrolimus 0.1% w/w is a topical ointment classified as a calcineurin inhibitor, primarily indicated for moderate to severe atopic dermatitis (eczema) in adults and children over 16 years when other treatments fail or are unsuitable. It suppresses immune responses by blocking T-cell activation, reducing inflammation, itching, and redness on affected skin areas like the face or body folds where steroids pose risks. Available as Protopic, this strength suits adults for twice-daily application on clean, dry skin, offering a steroid-sparing option for long-term management in non-immunocompromised patients. Off-label uses include certain ocular inflammations under specialist care.