Perrigo, a generic and over-the-counter drug maker, has urged its shareholders to reject Mylan NV's $27 billion tender offer to buy their shares.

According to Reuters, Perrigo said that Mylan NV, another generic and specialty pharmaceutical company, has severely undervalued the company.

As reported by Market Watch, Perrigo has announced that its Board of Directors has reviewed Mylan's unsolicited tender offer to acquire all of the outstanding shares of the company. Perrigo, in consolation with its financial and legal advisers, unanimously decided that the offer was undervaluing the company and does not adequately offer a fair compensation to the shareholders.

It was first reported that Mylan already proposed to buy Perrigo back in April. And after being repeatedly rebuffed, Mylan made a tender offer on Monday.

According to reports, Mylan would take control if more than 50 percent of Perrigo shares are tendered in the offer. This strategy done by Mylan was made possible under the takeover law in Ireland, Perrigo's place of incorporation since buying Irish drugmaker, Elan in 2013.

Mylan however said in a statment that, "an attempt by Perrigo to further frustrate the tender process and to prevent their shareholders from tendering to Mylan in support of this compelling, value creating transaction."

Perrigo was reported to have filed a Schedule 14D-9 with the Securities and Exchange Commission, detailing its reasons for the rejection of Mylan's offer.

As reported by Ledger Gazette, Mylan's CEO Heather Bresch said that, "Together, Mylan and Perrigo will create a unique and powerful force in our industry, with the scale, breadth and reach to create significant and sustained value for shareholders and all other stakeholders."

Regarding the details of Mylan NV's offer, the company offered to acquire all outstanding shares of Perrigo for $75 per share along with a swap of 2.3 Mylan ordinary shares for each ordinary Perrigo share.

However good that deal sounds like, Perrigo seems to be not buying it.