Karo Pharma AB said EQT Partners AB raised its offer for the company to 38.00 Swedish kronor per share in cash from 36.90 kronor announced earlier.
Stockholm-based Karo Pharma, which sells over the counter drugs and nutritional products, was valued at 5.97 billion kronor under the previous offer.
Swedish private equity firm EQT Partners' fund EQT VIII also extended the acceptance period for the revised offer to Jan. 17 from Jan. 4.
Karo Pharma's board unanimously recommended that shareholders accept the revised offer, made through EQT VIII fund's Karo Intressenter AB unit.
The company's directors Per-Anders Johansson and Anders Lönner, who was also Karo's executive chairman, accepted the previous offer.
Johansson and Lönner together held 21,942,140 shares in Karo Pharma, representing about 13.6% of the outstanding shares and votes in the company.
Lönner, however, died in December 2018 and was replaced by director Håkan Åström as acting chairman of the board.
The board found the revised offer to be more attractive compared to the previous offer, which was also found to be fair by Deloitte AB in October 2018.
Hamilton Advokatbyrå is acting as the legal adviser to Karo Pharma regarding the offer.
As of Jan. 2, US$1 was equivalent to 8.99 Swedish kronor.