  We consider constraints on cosmic strings from their emission of Higgs
particles, in the case that the strings have a Higgs condensate with amplitude
of order the string mass scale, assuming that a fraction of the energy of
condensate can be turned into radiation near cusps. The injection of energy by
the decaying Higgs particles affects the light element abundances predicted by
standard Big-Bang Nucleosynthesis (BBN), and also contributes to the Diffuse
Gamma-Ray Background (DGRB) in the universe today. We examine the two main
string scenarios (Nambu-Goto and field theory), and find that the primordial
Helium abundance strongly constrains the string tension and the efficiency of
the emission process in the NG scenario, while the strongest BBN constraint in
the FT scenario comes from the Deuterium abundance. The Fermi-LAT measurement
of the DGRB constrains the field theory scenario even more strongly than
previously estimated from EGRET data, requiring that the product of the string
tension {\mu} and Newton's constant G is bounded by G{\mu} <
2.7x10^{-11}{\beta}_{ft}^{-2}, where {\beta}_{ft}^2 is the fraction of the
strings' energy going into Higgs particles.
