In vivo 1H MRS can be used to detect and quantify the lactate resonance at 1.3 ppm provided that overlapping lipid resonances are eliminated. A homonuclear spectral editing method was developed to acquire uncontaminated 1H spectra of lactate with adiabatic pulses. An advantage of the adiabatic pulse sequence is the ability to induce uniform flip angles and to maximize sensitivity in applications employing surface coil transmitters which produce highly inhomogeneous B1. Glycolytic activity in an intracerebral C6 glioma in rats was monitored by using adiabatic editing sequences to observe [3‐13C]lactate produced from infused [1‐13C]glucose. Acute hyperglycemia (serum glucose >22 mM, n = 10) had no significant effect (P = 0.08) on the total ([12C]+ [13C]) tumor lactate signal intensity.