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Four new eremophilane-type sesquiterpenes, boeremialanes A–D (<b>1</b>–<b>4</b>) were obtained from solid substrate cultures of <i>Boeremia exigua</i> (Didymellaceae), an endophytic fungus isolated from <i>Fritillaria hupehensis</i> (Liliaceae). Boeremialanes A–C (<b>1</b>–<b>3</b>) are highly oxygenated eremophilanes with a benzoate unit attached at the C-13 position and are rarely found in nature. Their structures and absolute configurations were determined by extensive spectroscopic methods, electronic circular dichroism (ECD), and nuclear magnetic resonance (NMR) calculations with DP4+ analysis. Boeremialane D (<b>4</b>) potently inhibited nitric oxide production in lipopolysaccharide-treated RAW264.7 macrophages with an IC₅₀ of 8.62 μM and was more potent than the positive control, pyrrolidinedithiocarbamate (IC₅₀ = 23.1 μM).