We have studied extensively about Thithi Sandhi. The Thithi Sandhi period that lies between Amavasya and Pratipad thithi are called as "Kuugai Dosha". A person born during the last 12 minutes of Amavasya and the first 12 minutes of the following Sukla Paksha Pratipad are affected by this "Kuugai Dosha". If the Kuugai time also has Thiyajayam (We study this effects in detail later) and period is within 4 minutes (both within Amavasya and Pratipad thithi), then this "Kuugai Dosha" is considered as very acute. This Kuugai Dosha is considered as highly inauspicious. Let us see the effects of this "Kuugai Dosham". 1. The Kundali (Horoscope) of a person born during this Kuugai Dosha would remain non-functional and delivers confusing results. 2. The person (who are affected by this Kuugai Dosha) may not know the reason, why he is so unlucky. 3. Any events or work started during this period may not turn into success.