Activated carbon (AC) is a member of a family of carbons ranging from carbon blacks to nuclear graphite, from carbon fibers and composites to electrode graphite, and many more. All come from organic parent sources but with different carbonization and preparing processes. AC is a good adsorbent for gaseous and liquid adsorption and is widely applied in purification, de–colorization, removal of toxic substances, and treatment of waste water (Liu, 1998; Manocha, 2003; Yorgun et al., 2009; Sun and Jiang, 2010). This is because AC is regarded as a porous material that has a large specific surface area, a high adsorption capacity, chemical stability, and the ability to regenerate through desorption (Lu, 1994; Hsieh, 1998; Wu and Tseng, 2000; Huang, 2001). AC is classified into 5 types by size (dimension), shape (appearance), and purpose (Liu, 1998). Among all, activated carbon fibers (ACFs) are regarded as fibrous and porous material with a large specific surface area, a high adsorption capacity, and the ability to regenerate through absorption/desorption, as well as provide better characteristics such as a low–pressure drop to mass transfer and high contact efficiency due to their fibrous shape with a high aspect ratio (Asakura et al., 2004). Previous work (Lin, et al., 2015) established that to develop Wood–Based Activated Carbon Fibers Paperboard (WACFP) as a moisture–proof material, Nadelholz/ Laubholz Unbleached Kraft Pulp and cardboard from recycled cartons could be prepared into wood–based activated carbon fibers (WACFs) as part of WACFP. The biological action of WACFs was evaluated by Salmonella mutagenesis assay (Ames test), indicating that the WACFs had no cytotoxicity or mutagenicity in the test range (1.0–5.0 mg/plate of WACFs). The antimutagenicity against strains for the WACFs also suggested the safety of the WACFs used primarily as a material for food use. However, WACFs will probably be in contact with food directly or indirectly, and could even be eaten. It is necessary to undergo a mammalian test (biological safety assessment) after the Ames test, in accordance with Item 2, Article 3 of the Health Food Control Act and the Health Food Safety Assessment Method specified in the W.S.S.Z. No. 88037803 announcement from the Ministry of Health and Welfare, 1999. The biological safety assessment contains an acute toxicity test and subacute toxicity test (28–day feeding toxicity study). The feeding dose for acute and subacute toxicity tests was 5–10 times the maximum dose level for the subacute toxicity test (1.0 g/kg/day) specified by the Ministry of Health and Welfare (Ministry of Health and Welfare, 1999); meanwhile, the maximum dose as an antidote (1.0 g/kg) in the prevention and response manual (Emergency Response Information Center, 2006) writSafety Evaluation of Wood–Based Activated Carbon Fibers in a 28–day Feeding Study in Sprague–Dawley Rats