We consider the effect of a period of inflation with a high energy density upon the stability of the Higgs potential in the early universe .
The recent measurement of a large tensor-to-scalar ratio , r _ { T } \sim 0.16 , by the BICEP-2 experiment possibly implies that the energy density during inflation was very high , comparable with the GUT scale .
Given that the standard model Higgs potential is known to develop an instability at \Lambda \sim 10 ^ { 10 } GeV this means that the resulting large quantum fluctuations of the Higgs field could destabilize the vacuum during inflation , even if the Higgs field starts at zero expectation value .
We estimate the probability of such a catastrophic destabilisation given such an inflationary scenario and calculate that for a Higgs mass of m _ { h } = 125.5 GeV that the top mass must be less than m _ { t } \sim 172 GeV .
We present two possible cures : a direct coupling between the Higgs and the inflaton and a non-zero temperature from dissipation during inflation .