Background. Kutipraveshika Rasayana, the indoor modality of Rasayana therapy, is described in all the major classical texts but is very seldom performed. It requires a purpose-built three-chambered structure, an extensive course of preparatory purification, and residence in isolation for a period of weeks. Descriptive documentation of the regimen as delivered is largely absent from the published literature. Case presentation. This is a self-experiential report; the author is also the subject. A 33-year-old woman underwent Kutipraveshika Rasayana for 45 days in November and December 2016 at an Ayurvedic centre in Kerala, India, supervised by a physician who had himself undergone the regimen. Preparation extended over five and a half months and comprised Vamana, Virechana, a Karma Basti series of thirty enemas, Nasya and Shiravedha. Within the kuti the subject received Amalaki Rasayana prepared to the Charaka formulation, 100 g daily with 600 ml of milk until day 32 and 50 g daily with 300 ml of milk thereafter, together with six metallic preparations. The regimen was modified from the classical prescription of subdued light to the total darkness of the yogic variant, Kaya Kalpa. No efficacy endpoint was defined and none is claimed. Observations. Observations were recorded in a daily journal. The report documents the architecture of the Trigarbha Kuti and proposes the geometric mechanism by which it excludes light; complications arising from the conditions of the regimen rather than from any medication; circadian disruption from approximately day 21; persistent visual phenomena with full retention of insight and preserved spatial orientation; and two menstrual episodes differing markedly in severity. Re-exposure to light was carried out in four stages corresponding to the layers of the structure, and no photophobia followed. Verification of light-proofing proved possible only by a dark-adapted occupant, residual points of light being invisible to an observer entering from daylight. The regimen was completed without serious adverse event. Conclusion. Kutipraveshika Rasayana remains deliverable under contemporary conditions. This account provides a protocol, an architectural description with a proposed optical mechanism, and a record of the complications and adaptations that arise in practice, as a basis for a future prospective study.