Marilyn Lloyd sold 3 million shares at 450p, though the company denied the sale was related to the two bids for the group from Gehe of Germany and the UK's Unichem.
The company said Mrs Lloyd had disposed of her stake "solely with the view to diversifying her assets".
However, the sale will be viewed as an attempt by the controlling family to lock in profits ahead of the Monopolies and Mergers Commission investigations into the two bids. The shares dipped 4p to 465p on news of the sale.
Allen Lloyd retains 6.11 million shares worth pounds 28m and confirmed yesterday that he has "no intention" of selling his stake, "at least until the outcome of the MMC inquiry into the twin bids from Gehe and Unichem".
Both bids lapsed in March when they were referred to the MMC.
The British government said both bids raised competition concerns in the wholesale and European drugs markets.
The MMC must report its findings by the end of June and the final DTI announcement will be a month later.
It is possible that both bids will be blocked, which would cause a sharp fall in the Lloyds Chemists shares price
The prolonged bid battle for Lloyds has been supporting the shares though recent results have been disappointing. Last month the company warned that costs and uncertainties associated with the bid would hit this year's results.
First-half profits fell from pounds 26.6m to pounds 25.8m but the management said the full-year figures would be affected by bid costs of pounds 4m and further losses in its drug store outlets, where staff morale has been hit by the dragged-out bid process. Lloyds has lost managers and staff in its Health and Beauty chain. Losses in this renamed drugstores division tripled to pounds 1.32m.
This division may be targeted for disposal if one of the takeovers is successful.Reuse content