Life Pharmacy is planning to buy Pharmacybrands for $20 million in a merger that would give the combined group 30% of the market.
Life Pharmacy will pay Pharmacybrands' owners in shares, offering nearly 40 shares for every share in Pharmacybrands.
That values Pharmacybrands at $20 million and Life Pharmacy at just over $36 million.
Pharmacybrands runs Unichem, Amcal Chemists, Smart Pharmacy and Dispensary First.
The deal has the support of those controlling 69% of the company, including Cape Healthcare which owns 66%.
Life Pharmacy chief financial officer Craig Wilson says the two groups complement each other and the deal will allow them to cover community pharmacies to high end retail stores.
Mr Wilson says there few jobs will be lost or stores closed.
The merger requires the approval of both company's shareholders.