Yes. Although Time Lords can "live forever, barring accidents" ("The War Games"), they can still die. They can die if they expire before they can regenerate - as happens to the Doctor in the alternate timeline of "Turn Left" and is implied to have happened to the Doctor in "The Impossible Astronaut"; outside influences such as poison and anesthetic can also prevent regeneration, as seen in "Let's Kill Hitler" and the 1996 TV movie. "The Mind of Evil" reveals that the common drug Aspirin is a poison fatal to Time Lords. Regeneration is also not a guarantee of survival, as suggested by the Fifth Doctor's nearly failed regeneration in "Castrovalva" and the Doctor's fear of being killed in "The Unquiet Dead"; it has also been hinted that a regeneration could result in a form that cannot sustain life, such as the Ninth Doctor saying he could have no head after he changes ("The Parting of the Ways"). Regeneration can also be voluntarily stopped, as the Master did before he (apparently) died in "Last of the Time Lords". Lastly, a limit on the number of regenerations a Time Lord can have - 12, or 13 incarnations - was established in "The Deadly Assassin" and on several occasions, including in "The Twin Dilemma", we have seen Time Lords expire at the end of this, though the Master was able to stay alive through other means. However, "The Five Doctors" reveals that the limit is artificial, imposed by the High Council, who has the ability to renew it at will; they offer this to the Master in exchange for his help, and later do give the Master a new set of regenerations (as revealed in "The Sound of Drums"). Whether the limit still exists following the destruction of the Time Lords and Gallifrey in the Last Great Time War (as first revealed in "The End of the World") remains unknown. It was confirmed by the Eleventh Doctor in "The Time of the Doctor" that the limit is still in effect.