We present Stark widths and shifts of the Hα line measured in a flash tube plasma in the electron density range N_e = (1– 4) × 10¹⁸ cm⁻³ and the temperature range T = 1–2 eV. The plasma parameters were measured independently of the width and shift of the Hα line. We found that the Hα widths and shifts, measured at two different plasma sources, producing 'warm dense matter' of similar parameters—the underwater discharge and the flash tube—are consistent with each other. Our experimental results are in a good agreement with Oks' theory of Stark widths and shifts. As a conventional reference, we also compared our experimental results with Griem's theory of Stark widths and shifts. For Griem's shifts we found discrepancies of up to 76%. Griem's widths lie mostly within the experimental error bars; however, their rms deviation from the most probable experimental widths is up to 44% greater than for Oks' widths. Therefore our experiment provides further proof of some new warm-dense-matter effects incorporated in Oks' theory, the most important of which is the acceleration of the perturbing electrons by the ion field.